Apparatus and methods for use of expandable members in surgical applications

ABSTRACT

An apparatus includes a support member and a knob, each having an engagement portion. The support member is coupled to a shaft of a catheter assembly. The knob is configured to engage a stylet of the catheter assembly. The knob is configured to rotate relative to the support member through multiple discrete increments when the engagement portion of the knob is engaged with the engagement portion of the support member. Each discrete increment can be, for example, less than one revolution (e.g., thirty degrees of rotation).

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application Ser.No. 60/884,050, entitled “Apparatus and Methods for Use of ExpandableMembers in Surgical Applications,” filed Jan. 9, 2007, which isincorporated herein by reference in its entirety.

This application claims priority to U.S. Provisional Patent ApplicationSer. No. 60/823,566, entitled “Apparatus and Methods for Collapsing anExpandable Member of a Medical Device,” filed Aug. 25, 2006, which isincorporated herein by reference in its entirety

This application is related to U.S. patent application Attorney DocketNos. KYPH-032/01US 305363-2126, KYPH-032/02US 305363-2127 andKYPH-032/04US 305363-2152, each entitled “Apparatus and Methods for Useof Expandable Members in Surgical Applications,” filed on the same date,each of which is incorporated herein by reference in their entirety.

BACKGROUND

The invention relates generally to medical devices and procedures. Moreparticularly, in some embodiments, an apparatus comprises a catheterassembly and an expandable member for repairing bone defects, displacingtissue and/or compressing tissue.

Expandable members are used in various minimally-invasive medicalprocedures. When deployed, the expandable member may be exposed to roughsurfaces and/or high inflation pressures. Such an environment can causeabrasion, tearing and/or puncturing of the expandable member, therebyrendering them inoperative. Moreover, upon completion of suchprocedures, the expandable member is often returned to its collapsedconfiguration so that it can be removed from the patient's body, forexample, via a cannula. Even when placed in a collapsed configuration,however, expandable members can have a wall thickness and/or an overallsize such that even when in the collapsed configuration the balloons arenot easily removed through the cannula.

Some known medical devices are configured to wrap an expandable memberto reduce the size of the expandable member when in the collapsedconfiguration. Many of these medical devices, however, do not includecomponents, such as for example, a shaft, a connector or the like,configured to withstand the torsional stress caused by such twisting.

Some known medical devices are configured to wrap and/or fold theexpandable member to reduce the size of the expandable member when inthe collapsed configuration. Many of these medical devices, however, donot include any mechanism for controlling the rotation of the expandablemember.

Thus, a need exists for medical devices with expandable members havingimproved resistance against abrasion, tearing and/or puncturing for invarious medical applications. For example, a medical device having anexpandable member having multiple layers and/or coatings configured toresist tearing and puncturing may be desirable for use in environmentsin which the expandable member may contact hard, rough surfaces. Amedical device having a mechanism for controlling the rotation of anexpandable member may also be desirable. For example, an improvedmechanism for contracting an expandable member after deployment may beparticularly applicable in percutaneous medical procedures.

SUMMARY

Medical devices having expandable members are described herein. In someembodiments, an apparatus includes a support member and a knob, eachhaving an engagement portion. The support member is coupled to a shaftof a catheter assembly. The knob is configured to engage a stylet of thecatheter assembly. The knob is configured to rotate relative to thesupport member through multiple discrete increments when the engagementportion of the knob is engaged with the engagement portion of thesupport member. Each discrete increment can be, for example, less thanone revolution (e.g., thirty degrees of rotation).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic illustration showing a medical device accordingto an embodiment of the invention.

FIG. 1B is a schematic illustration showing a medical device accordingto an embodiment of the invention in which a twisting apparatus includesa first member having a ratchet wheel and a second member having a pawlportion configured to engage the ratchet wheel.

FIG. 2 is a schematic illustration showing a medical device according toan embodiment of the invention in which a twisting apparatus includes afirst member having a ratchet wheel and a second member having a pawlportion and being disposed about the first member.

FIG. 3 is a perspective view of a medical device according to anembodiment of the invention.

FIGS. 4 and 5 are cross-sectional perspective views of the portion ofthe medical device shown in FIG. 3 labeled as 4,5 in a firstconfiguration and a second configuration, respectively.

FIG. 6 is a front view of a portion of the medical device shown in FIG.3.

FIG. 7 is a cross-sectional perspective view of the twisting apparatusof the medical device shown in FIG. 3.

FIG. 8 is an exploded view of the twisting apparatus of the medicaldevice shown in FIG. 3.

FIGS. 9 through 11 show a perspective view, a cross-sectional view and afront view, respectively, of a ratchet wheel portion of the medicaldevice shown in FIG. 3.

FIGS. 12 through 14 show a perspective view, a top view and across-sectional view, respectively, of a housing portion of the medicaldevice shown in FIG. 3.

FIGS. 15 through 17 show a perspective view, a top view and across-sectional view, respectively, of a pawl portion of the medicaldevice shown in FIG. 3.

FIG. 18 is a perspective view of a spring shoulder portion of themedical device shown in FIG. 3.

FIG. 19 is a perspective view of an indicator portion of the medicaldevice shown in FIG. 3.

FIGS. 20 through 22 show a perspective view, a top view and across-sectional view, respectively, of a coupler portion of the medicaldevice shown in FIG. 3.

FIG. 23 is a schematic illustration showing the teeth portion of theratchet wheel and pawl portion of the medical device shown in FIG. 3.

FIG. 24 is a schematic illustration showing the teeth portion of theratchet wheel and pawl portion of a medical device according to anembodiment of the invention.

FIG. 25 is a perspective exploded view of a medical device according toan embodiment of the invention.

FIG. 26 is a cross-sectional view of the medical device shown in FIG.25.

FIG. 27 is a perspective exploded view of a medical device according toan embodiment of the invention.

FIG. 28 is a front view of a stylet portion of the medical device shownin FIG. 3.

FIG. 29 is a perspective view of a portion of the medical device shownin FIG. 3.

FIG. 30 is a perspective view of a twisting apparatus according to anembodiment of the invention.

FIG. 31 is a cross-sectional view of the twisting apparatus shown inFIG. 30.

FIG. 32 is a cross-sectional perspective view of the twisting apparatusshown in FIG. 30.

FIG. 33 is a perspective view of a portion of the twisting apparatusshown in FIG. 30.

FIG. 34 is a perspective view of a portion of the twisting apparatusshown in FIG. 30.

FIGS. 35 and 36 are cross-sectional views of a twisting apparatusaccording to an embodiment of the invention in a first configuration anda second configuration, respectively.

FIG. 37 is a perspective view of a portion of the twisting apparatusshown in FIGS. 35 and 36.

FIG. 38 is a perspective view of a portion of the twisting apparatusshown in FIGS. 35 and 36.

FIG. 39 is a perspective view of the expandable member shown in FIG. 3in an expanded configuration.

FIG. 40 is a schematic illustration of a portion of a catheter assemblyaccording to an embodiment of the invention having an outer shaft, aninner shaft and a stylet.

FIG. 41 is a schematic illustration of a portion of a catheter assemblyaccording to an embodiment of the invention having an outer shaft, aninner shaft, a stylet and a sleeve.

FIG. 42 is a front view of the expandable member shown in FIGS. 3 and 39in a collapsed configuration.

FIGS. 43 and 44 are cross-sectional views of the expandable member shownin FIG. 42 taken along line 43-43, in a twisted configuration and anuntwisted configuration, respectively.

FIG. 45 is a cross-sectional view of an expandable member according toan embodiment of the invention in a collapsed configuration.

FIG. 46 is a cross-sectional view of an expandable member according toan embodiment of the invention in an expanded configuration.

FIG. 47 is a cross-sectional view of an expandable member according toan embodiment of the invention in a collapsed configuration.

FIG. 48 is a cross-sectional view of an expandable member according toan embodiment of the invention in an expanded configuration, theexpandable member including an outer sheath covering a portion of aninner layer.

FIG. 49 is a perspective view of an expandable member according to anembodiment of the invention in an expanded configuration.

FIG. 50 is a perspective view of an expandable member according to anembodiment of the invention in an expanded configuration.

FIG. 51 is a flow chart of a method according to an embodiment of theinvention.

FIG. 52 is a flow chart of a method according to an embodiment of theinvention.

FIG. 53 is a flow chart of a method according to an embodiment of theinvention.

FIG. 54 is a flow chart of a method according to an embodiment of theinvention.

FIG. 55 is a flow chart of a method according to an embodiment of theinvention.

FIG. 56 is a flow chart of a method according to an embodiment of theinvention.

FIG. 57 is a flow chart of a method according to an embodiment of theinvention.

FIG. 58 is a flow chart of a method according to an embodiment of theinvention.

DETAILED DESCRIPTION

Medical devices having expandable members are described herein. In someembodiments, an apparatus includes a support member and a knob, eachhaving an engagement portion. The support member is coupled to a shaftof a catheter assembly. The knob is configured to engage a stylet of thecatheter assembly. The knob is configured to rotate relative to thesupport member through multiple discrete increments when the engagementportion of the knob is engaged with the engagement portion of thesupport member. Each discrete increment can be, for example, less thanone revolution (e.g., thirty degrees of rotation). In some embodiments,for example, the catheter assembly includes an expandable member coupledto the shaft and the stylet such that when the knob is rotated relativeto the support member, at least a portion of the expandable member istwisted about the catheter assembly.

In some embodiments, an apparatus includes an elongate assembly and anactuator. The elongate assembly has a first shaft and a second shaftdisposed within the first shaft. The first shaft is configured to becoupled to a proximal portion of an expandable member. The second shaftis configured to be coupled to a distal portion of the expandablemember. The actuator is configured to rotate the second shaft relativeto the first shaft through multiple discrete increments. In someembodiments, for example, the actuator can include a ratchet wheel havemultiple ratchet teeth and a pawl configured to engage the ratchetteeth, such that each discrete increment is associated with a ratchettooth.

In some embodiments, an apparatus includes a first member and a secondmember. The first member has a ratchet wheel and is coupled to acatheter. The second member has a pawl portion and engages a shaftrotatably disposed within the catheter. The pawl portion is configuredto engage the ratchet wheel to cooperatively resist the rotation of thesecond member with respect to the first member when the second memberand the first member are collectively in a first configuration. The pawlportion is configured to be spaced apart from the ratchet wheel when thesecond member and the first member are collectively in a secondconfiguration.

In some embodiments, an apparatus includes a support member and a knob.The support is configured to be coupled to a shaft of a catheterassembly. The knob is configured to engage an elongated member of thecatheter assembly rotatably disposed within the shaft of the catheterassembly. The knob is configured to rotate unidirectionally relative tothe support member when the support member and the knob are collectivelyin a first configuration. The knob is configured to rotatebidirectionally relative to the support member when the support memberand the knob are collectively in a second configuration. In someembodiments, the catheter assembly includes an expandable member havinga proximal end portion and a distal end portion. The proximal endportion of the expandable member is coupled to a distal end portion ofthe shaft. The distal end portion of the expandable member is coupled toa distal end portion of the elongated member. In this manner, when theknob is rotated relative to the support member, at least a portion ofthe expandable member is twisted about a longitudinal axis of thecatheter assembly.

In some embodiments, an apparatus includes a catheter assembly, anexpandable member and an actuator. The catheter assembly has a firstshaft and a second shaft disposed within the first shaft. The expandablemember has a proximal portion coupled to the first shaft and a distalportion coupled to the second shaft. The actuator is configured torotate the second shaft relative to the first shaft in a first directionto twist at least a portion of the expandable member about a centerlineof the second shaft. The actuator is configured to prevent rotation ofthe second shaft relative to the first shaft in a second directionopposite the first direction.

In some embodiments, an apparatus includes an elongated member, anexpandable member coupled to the elongated member, and an outer sheath.The outer sheath, which can be constructed from a different materialthan the expandable member, is disposed about the expandable member suchthat an outer surface of the expandable member is in discontinuouscontact with an inner surface of the outer sheath. The expandable memberand the outer sheath are configured to cooperatively displace a bonestructure when moving between a collapsed configuration and an expandedconfiguration.

In some embodiments, an apparatus includes an elongated member, anexpandable member, an outer sheath and a clamp. The expandable member iscoupled to the elongated member and is constructed from a firstmaterial, such as, for example, Nylon 12. The outer sheath is disposedabout the expandable member and is constructed from a second materialdifferent than the first material, such as Teflon. The clamp isconfigured to couple the outer sheath to the expandable member.

In some embodiments, an apparatus includes an elongated member and anexpandable member. The expandable member is coupled to the elongatedmember and is configured to displace a first portion of a spine relativeto a second portion of the spine when moving between a collapsedconfiguration and an expanded configuration. The expandable memberincludes a first layer and a second layer. The first layer isconstructed from a first polymer. The second layer is disposed about thefirst layer and is constructed from a second polymer, different than thefirst polymer. The second polymer has a molecular structure that is moreamorphous than the molecular structure of the first polymer. In someembodiments, the elongated member can further include an actuatorconfigured to twist at least a portion of the expandable member aboutthe elongated member through a predetermined number of rotations.

In some embodiments, an apparatus includes an elongated member and anexpandable member. The expandable member is coupled to the elongatedmember and includes a first layer and a second layer. The first layer isconstructed from a first material having a lubricity. The second layeris disposed about the first layer and is constructed from a secondmaterial having a lubricity greater than the lubricity of the firstmaterial. The elongated member can further include an actuatorconfigured to twist the expandable member about the elongated member,the actuator including a ratchet.

In some embodiments, an apparatus includes an elongated member and anexpandable member configured to displace bone. The expandable member iscoupled to the elongated member and includes an abrasion-resistantcoating disposed about a portion of an outer surface of the expandablemember. The expandable member defines multiple pleats when in acollapsed configuration. In some embodiments, the elongated member canfurther include an actuator configured to twist the expandable memberabout a longitudinal axis of the elongated member.

In some embodiments, an apparatus includes an expandable member and anelongate assembly. The expandable member is configured to displace afirst portion of a bone structure relative to a second portion of thebone structure when moved from a collapsed configuration to an expandedconfiguration. The elongate assembly includes a shaft and an elongatedmember disposed with a lumen defined by the shaft. A proximal endportion of the expandable member is coupled to a distal end portion ofthe shaft such that the proximal end portion of the expandable memberdoes not rotate relative to the distal end portion of the shaft when atleast a portion of the expandable member is twisted about the elongatedmember through at least four revolutions. A distal end portion of theexpandable member is coupled to a distal end portion of the elongatedmember such that the distal end portion of the expandable member doesnot rotate relative to the distal end portion of the elongated memberwhen at least the portion of the expandable member is twisted about theelongated member through at least four revolutions.

In some embodiments, an apparatus includes an expandable member, anelongate assembly and a sleeve. The expandable member is configured todisplace a first portion of a spine relative to a second portion of thespine when moved from a collapsed configuration to an expandedconfiguration. The elongate assembly includes a shaft, an elongatedmember rotatably disposed within the shaft, and a stylet disposed withinthe elongated member. At least a portion of the stylet is bonded to atleast a first portion of the elongated member. The sleeve is disposedbetween an outer surface of the elongated member and an inner surface ofthe expandable member. The sleeve is coupled to the distal end portionof the expandable member and a second portion of the elongated member.In some embodiments, the second portion of the elongated member can bedifferent than the first portion of the elongated member.

In some embodiments, an apparatus includes an expandable member, a shaftand an elongated member rotatably disposed within the shaft. Theexpandable member is configured to displace a first portion of a bonestructure relative to a second portion of the bone structure when movedfrom a collapsed configuration to an expanded configuration. The shafthas a distal end portion coupled to a proximal end portion of theexpandable member. A distal end portion of the elongated member iscoupled to a distal end portion of the expandable member. The shaft isconfigured to have an angle of twist between a proximal end portion ofthe shaft and the distal end portion of the shaft of less than onehundred eighty degrees when at least a portion of the elongated memberis rotated relative to the shaft through at least four revolutions.

In some embodiments, an apparatus includes a catheter assembly and anexpandable member. The expandable member is configured to displace bonewhen moving between a collapsed configuration and an expandedconfiguration. The catheter assembly includes an outer shaft, an innershaft, a stylet and a twisting apparatus. A portion of the inner shaftis movably disposed within the outer shaft. Similarly, a portion of thestylet is disposed within the inner shaft. At least one of the stylet orthe inner shaft is coupled to a distal end portion of the expandablemember. Similarly, the outer shaft is coupled to a proximal end portionof the expandable member. The twisting apparatus is coupled to the outershaft and the stylet and is configured to rotate the stylet within theouter shaft to twist the expandable member about the stylet. At leastone of the outer shaft, the inner shaft or the stylet being constructedof a polymer reinforced with nano-particles.

In some embodiments, a method includes disposing a first portion of anexpandable member about a first catheter shaft and a second portion ofthe expandable member about a second catheter shaft. An adhesive isdisposed between the second portion of the expandable member and thesecond catheter shaft. An induction coil is disposed about the firstcatheter shaft without being in physical contact with the first cathetershaft or the second catheter shaft. An alternating current is suppliedto the indication coil, thereby producing a magnetic field about thefirst catheter shaft, which induces a current within the first cathetershaft. The alternating current is supplied for a predetermined timeperiod, during which the first portion of the expandable member changesfrom a solid to a liquid. The alternating current is then removed,allowing the first portion of the expandable member to solidify.

In some embodiments, a method includes coupling, to an elongated member,an expandable member configured to displace a first portion of a spinerelative to a second portion of the spine when moving between acollapsed configuration and an expanded configuration. An outer sheathis disposed about the expandable member. A clamp is placed about aportion of the outer sheath to couple the outer sheath to the expandablemember.

In some embodiments, a method includes bonding a portion of a styletwithin an elongated member. A proximal end portion of an expandablemember is coupled to a distal end portion of a shaft defining a lumen.The elongated member is disposed within the lumen of the shaft such thata distal end portion of the elongated member extends from the distal endportion of the shaft. A sleeve is disposed about the distal end portionof the elongated member. A distal end portion of the expandable memberis coupled to the distal end portion of the elongated member.

In some embodiments, a method includes moving an actuator from a firstposition to a second position such that a first shaft is rotatablerelative to a second shaft. The second shaft is disposed within thefirst shaft and coupled to an expandable member. The actuator is movedfrom the second position to the first position such that the secondshaft is rotatable relative to the first shaft through a plurality ofdiscrete increments.

In some embodiments, a method includes engaging a ratchet of a firstmember coupled to a first shaft with a pawl portion of a second membercoupled to a second shaft such that the second shaft can rotate relativeto the first shaft in a first direction. The second shaft is coupled toan expandable member. The ratchet of the first member is disengaged fromthe pawl portion of the second member such that that the second shaftcan rotate relative to the first shaft in a second direction oppositethe first direction.

In some embodiments, a method includes inserting into a body a catheterassembly including a shaft and an expandable member coupled to theshaft. The expandable member is moved from a first collapsedconfiguration to an expanded configuration. The expandable member ismoved from the expanded configuration to a second collapsedconfiguration, after the moving the expandable member from the firstcollapsed configuration. The expandable member is rotated about acenterline of the shaft through a plurality of discrete increments.

In some embodiments, a method includes inserting into a vertebral body adistal portion of a catheter assembly. The catheter assembly includes ashaft and an expandable member coupled to the shaft. The expandablemember is moved from a first collapsed configuration to an expandedconfiguration after the inserting. The expandable member is moved fromthe expanded configuration to a second collapsed configuration after themoving the expandable member from the first collapsed configuration. Aknob coupled to a proximal portion of the catheter assembly is rotatedin a first direction such that the expandable member is twisted about acenterline of the shaft. The knob is configured to resist rotation in asecond direction opposite the first direction. The distal portion of thecatheter assembly is removed from the vertebral body.

In some embodiments, a method includes inserting an expandable memberinto an interior portion of a bone structure. The expandable memberincludes a first layer and a second layer disposed about the first layersuch that an outer surface of the first layer is in discontinuouscontact with an inner surface of the second layer. The first layer isconstructed from a first polymer having a molecular structure. Thesecond layer is constructed from a second polymer having a molecularstructure more amorphous than the molecular structure of the firstpolymer. The expandable member is expanded while disposed within theinterior portion of the bone structure such that the expandable memberexerts a force sufficient to cause a first portion of the bone structureto move relative to a second portion of the bone structure.

In some embodiments, a method includes inserting into a body a catheterassembly. The catheter assembly includes an expandable member, a shafthaving a distal end portion coupled to a proximal end portion of theexpandable member, and an elongated member rotatably disposed within theshaft. A distal end portion of the elongated member is coupled to adistal end portion of the expandable member. The expandable member ismoved from a collapsed configuration to an expanded configuration. Theexpandable member is moved from the expanded configuration to thecollapsed configuration. At least a portion of the elongated member isrotated relative to the shaft such that at least a portion of theexpandable member is twisted about the elongated member through at leastfour revolutions while maintaining a fluid-tight seal between the distalend portion of the expandable member and the distal end portion of theelongated member.

In some embodiments, a method includes inserting a distal portion of acannula into a patient's body to establish a percutaneous path to atissue in the patient's body (e.g., a vertebral body). A ballooncatheter having a balloon in a contracted and/or twisted configurationis inserted into the cannula, and the balloon is advanced into thetissue. Once the balloon is positioned within the tissue, a twistingapparatus disposed on the proximal portion of the balloon catheter isactuated to rotate the balloon relative to the catheter. In this manner,the balloon can be placed in an un-twisted configuration after beingdisposed inside the tissue. In some embodiments, for example, thetwisting apparatus can include a counter to indicate the number ofrotations through which the balloon has been rotated. Alternatively, thetwisting apparatus can be configured such that after a pre-definednumber of rotations have been applied, further rotation of the twistingapparatus will not lead to further un-twisting of the balloon. In yetother embodiments, the twisting apparatus can include a ratchet and/or alocking mechanism to prevent undesired un-twisting of thetwisted/contracted balloon.

Once the balloon is un-twisted, a fluid is introduced through thecatheter into the balloon to inflate the balloon. In some embodiments,the inflation of the balloon may result in a cavity being formed withinthe tissue. For example, in some embodiments, the balloon can bepositioned within a bone structure having a first cortical wall, asecond cortical wall and cancellous bone portion disposed within thefirst and the second cortical walls. The inflation of the balloon canresult in the compression of at least portion of the cancellous boneportion, thereby forming the cavity. Moreover, in some embodiments, theinflation of the balloon can cause the first cortical wall to move inrelation to the second cortical wall, thereby increasing the distancebetween the first cortical wall and the second cortical wall. In someembodiments, for example, the pressure of the fluid inside the balloonmay need to be maintained between 1.4 MPa and 2.8 MPa (200 psi and 400psi) to produce a lifting force sufficient to move the first corticalwall away from the second cortical wall.

Once the cavity is formed within the tissue, the fluid is then withdrawnfrom the balloon to deflate the balloon. The balloon is then rotated viathe twisting apparatus to further reduce the profile of the balloon. Asdescribed herein, in some embodiments, the twisting apparatus caninclude a ratcheting mechanism such that the balloon can be twisted in acontrolled and/or incremental fashion. After the balloon has beensufficiently twisted, the balloon is then withdrawn from the patient'sbody via the cannula.

The term “expandable member” as used herein includes a component of amedical device that is configured to be changed or moved from acollapsed configuration to an expanded configuration in which theexpandable member is larger than in the collapsed configuration. In somevariations, the expandable member is configured to be expanded, forexample, by introducing a medium such as liquid and/or gas into theinterior of the expandable member. The expandable member can be, forexample, a balloon configured to expand from a collapsed configurationto an expanded configuration. In some applications, the balloon isconstructed, at least in part, from a low-compliant material.

As used in this specification, the singular forms “a,” “an” and “the”include plural referents unless the context clearly dictates otherwise.Thus, for example, the term “a member” is intended to mean a singlemember or a combination of members, “a material” is intended to mean oneor more materials, or a combination thereof. Furthermore, the words“proximal” and “distal” refer to the direction closer to and away from,respectively, an operator (e.g., surgeon, physician, nurse, technician,etc.) who would insert the medical device into the patient, with thetip-end (i.e., distal end) of the device inserted inside a patient'sbody first. Thus, for example, the end of a medical device firstinserted inside the patient's body would be the distal end, while theopposite end of the medical device (e.g., the end of the medical devicebeing operated by the operator) would be the proximal end of the medicaldevice.

FIG. 1A is a schematic illustration of a medical device 1 according toan embodiment of the invention. The medical device 1 includes a twistingapparatus 10 configured to be coupled to a catheter 2. The catheter 2 iscoupled to an elongated member 4, such as, for example, a stylet, atube, a rod, a cannula an/or a combination thereof, such that theelongated member 4 can be moved relative to the catheter 2. Theelongated member 4 is coupled to an expandable member 5. The expandablemember 5 is also coupled to the catheter 2 such that movement of theelongated member 4 relative to the catheter 2 causes the expandablemember 5 to be twisted and/or folded. Although the elongated member 4 isshown as being indirectly coupled to the catheter 2 via the expandablemember 5 and/or the twisting apparatus 10, in other embodiments theelongated member 4 can be directly coupled to the catheter 2. Forexample, in some embodiments, the elongated member 4 can be directlycoupled to the catheter 2 via a bearing, a retention surface or the like(none of which are shown in FIG. 1A).

The twisting apparatus 10 has a first member 20 and a second member 60.The first member 20 is coupled to the catheter 2 and has an engagementportion 30. The engagement portion 30 may also be referred to as aratchet portion, a clutch portion or a locking portion. The secondmember 60 is engaged with a portion of the elongated member 4 such thatmovement of the second member 60 causes the elongated member 4 to movein a similar fashion. The second member 60 includes an engagementportion 61, which may also be referred to as a pawl portion. Theengagement portion 61 of the second member 60 is configured to beremovably engaged with the engagement portion 30 of the first member 20(as indicated by the arrows Z) such that the movement of the secondmember 60 relative to the first member 20 can be controlled, therebycontrolling the twisting and/or folding of the expandable member 5.

In some embodiments, for example, the engagement portion 61 of thesecond member 60 is configured to be removably engaged with theengagement portion 30 of the first member 20 such that when theengagement portion 61 of the second member 60 is engaged with theengagement portion 30 of the first member 20, the second member 60 canbe rotated relative to the first member 20 through multiple discreteincrements. Such discrete increments can be, for example, predefineddiscrete increments (e.g., one quarter of a turn, one full turn, etc.).Conversely when the engagement portion 61 of the second member 60 isengaged with the engagement portion 30 of the first member 20, thesecond member 60 can be rotated relative to the first member 20 in ancontinuous, uninterrupted fashion.

As described in more detail herein, in some embodiments, a twistingapparatus can include a ratcheting, clutching and/or locking mechanism,such that once the elongated member is rotated in a first direction(e.g., clockwise relative to the catheter), the ratcheting mechanism canprevent the elongated member from rotating in a second direction (e.g.,counter-clockwise relative to the catheter). In this manner, thetwisting apparatus can allow the operator to twist the expandable memberthrough multiple rotations of the elongated member relative to thecatheter in a controlled and/or incremental fashion. Moreover, theratcheting mechanism can prevent the elongated member from “springingback” (e.g., rotating in the second direction) due to the increasedtension and/or torque produced by the twisting of the expandable memberabout the catheter, thus allowing the user to wrap the expandable membervery tightly about the catheter. In some embodiments, the twistingapparatus can include a release such that the operator can disengage theratcheting mechanism to allow counter rotation of the elongated member,thus allowing the expandable member to be untwisted.

As described in more detail herein, in some embodiments, a twistingapparatus can be configured with a counter to indicate the number ofrotations through which the expandable member has been rotated. Such acounter can be configured to provide an indication of the number ofrotations in a single direction. Alternatively, a counter can beconfigured to provide an indication of the number of rotation in both aclockwise and a counter clockwise direction. In some embodiments, thecounter is configured to provide a visual indicator of the number ofrotations through which the expandable member has been rotated.

In some embodiments, as described in more detail herein, a twistingapparatus can also be configured with a mechanism to preventover-rotation of the expandable member. For example, in someembodiments, a twisting apparatus can be configured to allow only sixclockwise rotations of the elongated member in relation to the catheter.In some embodiments, a “rotation limiting” twisting apparatus canprevent further rotation of the twisting apparatus once the expandablemember has been rotated a predetermined number of rotations. In otherembodiments, a rotation limiting twisting apparatus can allow unlimitedrotation of the twisting apparatus, however, once the expandable memberhas been rotated a predetermined number of rotations, further twistingof the twisting apparatus will not lead to further rotation of theelongated member relative to the catheter.

Although the catheter 2 is shown as being spaced apart from theelongated member 4, each of which is coupled to the same end portion ofan expandable member, in some embodiments, a medical device can includean elongated member coaxially and rotatably positioned within thecatheter. In such embodiments, for example, a distal portion of thecatheter can be coupled to a proximal portion of an expandable member(e.g., balloon). A distal portion of the elongated member can be coupledto a distal portion of the expandable member. A twisting apparatus ofthe type described herein can couple the catheter to the elongatedmember such that the elongated member can be rotated relative to thecatheter, resulting in the twisting or un-twisting of the expandablemember. In some embodiments, the twisting apparatus can be connected tothe proximal end of the catheter and/or the proximal end of theelongated member.

FIG. 1B is a schematic illustration of a cross-sectional view of amedical device 101 according to an embodiment of the invention. Themedical device 101 includes a twisting apparatus 100 configured to becoupled to a catheter 102. The catheter 102 has an outer shaft 103 thatdefines a lumen through which a portion of an elongated member 104, suchas, for example, a stylet, is disposed. The elongated member 104 has adistal end portion 107 coupled to an expandable member 105 and aproximal end portion 106. The expandable member 105 is also coupled tothe outer shaft 103 such that rotation of the elongated member 104relative to the outer shaft 103 causes the expandable member 105 to betwisted about a longitudinal axis L of the catheter 102.

The twisting apparatus 100 has a first member 120, a second member 160and a biasing member 154. The distal end portion 126 of the first member120 is coupled to the catheter 102. The first member 120 defines a lumen123 through which the elongated member 104 is disposed and has a ratchetwheel 130 disposed at a proximal end portion 127 of the first member120. The second member 160 defines an engagement portion 177 configuredto engage the proximal end portion 106 of the elongated member 104 suchthat rotation of the second member 160 about the longitudinal axis Lcauses the elongated member 104 to rotate about the longitudinal axis L,as indicated by arrows A and B. The second member 160 includes a pawlportion 161 configured to engage the ratchet wheel 130 of the firstmember 120 such that the rotation of the second member 160 relative tothe first member 120 can be controlled, thereby controlling the rotationof the elongated member 104. The biasing member 154 engages a portion ofthe second member 160 such that engagement between the pawl portion 161and the ratchet wheel 130 is maintained. In use, the pawl portion 161can be disengaged from the ratchet wheel 130 by applying an externalforce to counteract the biasing member 154.

FIG. 2 is a schematic illustration of cross-sectional view of a medicaldevice 201 according to an embodiment of the invention. The medicaldevice 201 includes a twisting apparatus 200 configured to be coupled toa catheter 202 having an outer shaft 203 that defines a lumen throughwhich a portion of an elongated member 204 is disposed. A distal endportion 207 of the elongated member 204 is coupled to an expandablemember 205. As described above, the expandable member 205 is alsocoupled to the outer shaft 203 such that rotation of the elongatedmember 204 relative to the outer shaft 203 causes the expandable member205 to be twisted about a longitudinal axis L of the catheter 202, asindicated by arrows C and D.

The illustrated twisting apparatus 200 has a first member 220, a secondmember 260 and a biasing member 254. A portion of the first member 220is coupled to the catheter 202. The first member 220 defines a lumen 223through which a portion of the elongated member 204 is disposed and hasa ratchet wheel 230 disposed on its outer side wall 222. The secondmember 260 defines an engagement portion 277 configured to engage theproximal end portion 206 of the elongated member 204 such that rotationof the second member 260 about the longitudinal axis L causes theelongated member 204 to rotate about the longitudinal axis L. The secondmember 260 includes a pawl portion 261 disposed on the side wall 222 ofthe second member 260. As described above, the pawl portion 261 isconfigured to engage the ratchet wheel 230 of the first member 220 suchthat the rotation of the second member 260 relative to the first member220 can be controlled. The biasing member 254 engages a portion of thesecond member 260 such that engagement between the pawl portion 261 andthe ratchet wheel 230 is maintained.

Although the elongated members described herein are shown and describedas being disposed within a portion of the catheter and a portion of thetwisting apparatus, in other embodiments, an elongated member can bedisposed outside of the catheter and/or the twisting apparatus. In yetother embodiments, an elongated member can be positioned such that itslongitudinal axis is not parallel and/or coincident with thelongitudinal axis of the catheter and/or the twisting apparatus.

FIG. 3 is a perspective view of a medical device 301 according to anembodiment of the invention that includes a actuator 300 coupled to acatheter assembly 302 via coupler 314. The illustrated catheter assembly302 has a Y-connector 309 and an outer shaft 303 that defines a lumenthrough which a portion of a stylet 304 (see FIG. 6) is disposed. Thecatheter assembly 302 includes an expandable member 305 coupled to adistal portion of the outer shaft 303 and a distal portion of the stylet304. In this manner, rotation of the stylet 304 relative to the outershaft 303 causes at least a portion of the expandable member 305 to betwisted about the stylet 304.

As described in more detail herein, in some embodiments, the expandablemember 305 is configured to be inserted into a body via a cannula (notshown in FIG. 3). Accordingly, in some embodiments, the actuator 300 isconfigured to twist at least a portion of the expandable member 305about the stylet 304 such that the expandable member 305 can be removedvia the cannula. Said another way, in some embodiments, the actuator 300is configured twist at least a portion of the expandable member 305about the stylet 304 such that the profile (e.g., the outer diameter) ofthe expandable member 305 is less than the diameter of the cannula. Insome embodiments, for example, the medical device 301 is configuredtwist at least a portion of the expandable member 305 about the stylet304 through at least three revolutions. In other embodiments, themedical device 301 is configured twist at least a portion of theexpandable member 305 about the stylet 304 through at least fourrevolutions. In yet other embodiments, the medical device 301 isconfigured twist at least a portion of the expandable member 305 aboutthe stylet 304 through at least six revolutions.

FIG. 6 is a front view of the catheter assembly 302 decoupled from theactuator 300. As described above, the catheter assembly 302 has an outershaft 303 that defines a lumen through which a portion of a stylet 304is disposed. An expandable member 305 is coupled to a portion of theouter shaft 303 and a distal end portion 307 of the stylet 304. Theouter shaft 303 is coupled to a Y-connector 309, which can be incommunication with an inflation lumen (not shown) of the catheterassembly 302. In some embodiments, the Y-connector can include a valveto selectively place the inflation lumen in fluid communication with aninflation devices (e.g., a syringe, a source of pressurized fluid or thelike). In some embodiments, for example, the Y-connector can include acheck valve (e.g., a “one-way” valve) to control the direction of theflow of fluid into the inflation lumen. A luer cap 310 is disposed atthe proximal end of the catheter assembly 302. The proximal end portion306 of the stylet 304 extends beyond the luer cap 310 and includes aengagement portion 308 configured to be received by the actuator 300, asdescribed herein. In some embodiments, the luer cap 310 can beconstructed from a suitable polymer, such as polycarbonate.

Although shown as including a linear outer shaft and a stylet disposedtherein, in some embodiments, as discussed in more detail herein, acatheter assembly can include any number of shafts, tubes and/or othercomponents. For example, in some embodiments, the catheter assembly caninclude an outer shaft, an inner shaft and a stylet disposed within theinner shaft, similar to the catheter disclosed in U.S. Pat. No.6,719,773, which is incorporated herein by reference in its entirety. Inother embodiments, a catheter assembly can be devoid of a stylet andinclude only an outer shaft and an inner tube coupled to an expandablemember, the inner tube being configured to rotate within the outer shaftto cause the expandable member to be twisted and/or folded as describedherein. In other embodiments, the catheter can include an inner shaftdefining a lumen configured to receive a portion of a guide wire. In yetother embodiments, the catheter assembly can include other components,such as a strain relief member configured to improve the strength at theconnection between the Y-connector and the outer shaft, an insertionsleeve configured to protect the expandable member during insertion andremoval and/or a distal sleeve.

Moreover, in some embodiments, a catheter assembly can include one ormore non-linear portions. For example, in some embodiments, a catheterassembly can include an outer shaft having a curved portion. In otherembodiments, the outer shaft and/or the stylet can be flexible.

FIGS. 4 and 5 are cross-sectional views of the portion of the medicaldevice 301 shown in FIG. 3 labeled as 4,5 showing the actuator 300 in afirst configuration and a second configuration, respectively. FIG. 7 isa cross-sectional view of the actuator 300 decoupled from the catheterassembly 302. FIG. 8 is an exploded view of the actuator 300 decoupledfrom the catheter assembly 302. The illustrated actuator 300 includes afirst member 320 and second member 360 disposed about the first member320. The first member 320 includes a distal end portion 326 and aproximal end portion 327. The distal end portion 326 of the first member320 is coupled to the luer cap 310 via coupler 314, such that the firstmember 320 cannot move relative to the catheter assembly 302. Theproximal end portion 327 of the first member 320 includes a ratchetwheel 330 removably engagable with a pawl portion 361 of the secondmember 360. The first member 320 defines a lumen 323 through which aportion of the stylet 304 is disposed such that the stylet 304 canrotate about longitudinal axis L relative to the first member 320.

The second member 360 includes a housing portion 372 and a pawl portion361 removably engagable with the ratchet wheel 330 of the first member320. The housing portion 372 defines a lumen 377 within which the firstmember 320 is disposed. The housing portion 372 has a knob portion 373and a spring engagement portion 376 disposed at its distal end 374. Asillustrated, the spring engagement portion 376 is engaged with one endof a spring 354. The other end of the spring 354 is engaged with aspring shoulder 350 disposed about the first member 320. In this manner,the force from the spring 354 acts to move the second member 360distally relative to the first member 320 such that the pawl portion 361and the ratchet wheel 330 remain engaged (i.e., the first configurationas illustrated in FIG. 4).

The pawl portion 361 of the second member 360 is fixedly coupled to thehousing portion 372 and defines an opening 381 within which theengagement portion 308 of the stylet 304 is received. As illustrated inFIGS. 15 through 17, opening 381 has a long, narrow shape such that whenthe second member 360 rotates, the engagement portion 308 will engagethe sides of the opening 381 thereby causing the stylet 304 to rotatewith the second member 360. Moreover, because the engagement portion 308is not coupled to the second member 360, the second member 360 can moveaxially relative to the stylet 304.

As illustrated in FIGS. 8 through 11, the ratchet wheel 330 of the firstmember 320 includes multiple teeth 331. Similarly, as illustrated inFIGS. 8 and 15 through 17, the pawl portion 361 of the second member 360includes multiple teeth 362 configured to engage the teeth 331 on theratchet wheel 330. As illustrated in FIG. 23, the teeth 331 on theratchet wheel 330 each include a first retention surface 332 and asecond retention surface 333 that collectively define a multiplerecesses and protrusions that characterize the teeth 331. Similarly, theteeth 362 on the pawl portion 361 each include a first retention surface363 and a second retention surface 364 that collectively define multiplerecesses and protrusions that characterize the teeth 362 of the pawlportion 361. The first retention surfaces 363 of the pawl portion 361are configured to complimentarily couple (e.g., mate) with the firstretention surfaces 332 of the ratchet wheel 330. Similarly, the secondretention surfaces 364 of the pawl portion 361 are configured tocomplimentarily couple (e.g., mate) with the second retention surfaces333 of the ratchet wheel 330. The first retention surfaces 332, 363 areeach substantially parallel to the longitudinal axis L, whereas thesecond retention surfaces 333, 364 are each at an angle Θ to thelongitudinal axis L. In this manner, because the second retentionsurfaces 333, 364 are at an angle to the longitudinal axis L, the pawlportion 361 can move relative to the ratchet wheel 330 as indicated bythe arrow J in FIG. 23 when the pawl portion 361 is engaged with theratchet wheel 330. Said another way, when a rotational force is appliedto the pawl portion 361, as indicated by the arrow J, the contactbetween the angled retention surfaces 333, 364 produces a resultantforce F_(L) on the pawl portion 361 that is parallel to the longitudinalaxis L and in the proximal direction. Accordingly, when the resultantforce F_(L) is sufficient to overcome the force produced by the spring354, the pawl portion 361 moves along the longitudinal axis L in aproximal direction away from the ratchet wheel 330, thereby allowing thepawl portion 361 to move as indicated by the arrow J.

Similarly, when a rotational force is applied to the pawl portion 361,as indicated by the arrow J, the contact between the angled retentionsurfaces 333, 364 produces a resultant force F_(R) on the pawl portion361 that opposes rotation in the direction as indicated by arrow J.Accordingly, when the actuator 300 is in its first (e.g., engaged)configuration (see FIG. 4), the pawl portion 361 and the ratchet wheel330 cooperatively resist the rotation of the second member 360 relativeto the first member 320. Such resistance can provide the user withbetter control when rotating the second member 360 relative to the firstmember 320.

Conversely, when a rotational force is applied to the pawl portion 361,as indicated by the arrow K, because the first retention surfaces 332,363 are substantially parallel to the longitudinal axis L, no resultantforce F_(L) is produced when the first retention surfaces 332, 363contact each other. Accordingly, the pawl portion 361 cannot moverelative to the ratchet wheel 330 in the direction as indicated by thearrow K in FIG. 23 when the pawl portion 361 is engaged with the ratchetwheel 330.

Referring again to FIGS. 4 and 5, when the actuator 300 is in its first(e.g., engaged) configuration (see FIG. 4), the second member 360 (andtherefore the stylet 304) can be rotated relative to the first member320 about the longitudinal axis L in a direction as indicated by arrowE. The second member 360 cannot, however, be rotated in a direction asindicated by arrow F. As such, the expandable member 305 can be twistedand/or folded in a unidirectional fashion.

Moreover, when the actuator 300 is in its first configuration and thesecond member 360 is rotated in a direction as indicated by arrow E, theforce exerted by the spring 354 urges the pawl portion 361 towards theratchet wheel 360 when the tip portions (i.e., the protrusions) of theteeth 362 move past the tip portions (i.e., the protrusions) of theteeth 331. Accordingly, the tip portions of the teeth 362 of the pawlportion 361 snap into the corresponding recesses of the teeth 331 of theratchet wheel 360. In this manner, the second member 360 can be rotatedrelative to the first member 320 in a controlled and/or incrementalfashion. Said another way, when the actuator 300 is in its first (e.g.,engaged) configuration, the second member 360 can be rotated relative tothe first member 320 in a direction as indicated by arrow E through aset of discrete increments.

Each of the discrete increments is associated with the recesses and/orprotrusions of the teeth 362 of the pawl portion 361 and/or the recessesand/or protrusions of the teeth 331 of the ratchet wheel 360. Saidanother way, the size of each discrete is proportional to the number ofteeth 362 of the pawl portion 361 and/or the number of teeth 331 of theratchet wheel 360. The size of each discrete increment can be anysuitable amount. In some embodiments, for example, each discreteincrement can be approximately thirty degrees of one revolution (e.g.,when the number of teeth is twelve). In other embodiments, each discreteincrement can be approximately one revolution. In yet other embodiments,the discrete increments can be non-uniform in size (e.g., the size ofthe increment decreases as a function of the angular position of thepawl portion 361 relative to the ratchet wheel 330.

In addition to allowing the pawl portion 361 to rotate relative to theratchet wheel 330 through multiple discrete increments, the engagementof the teeth 362 of the pawl portion 361 and the teeth 331 of theratchet wheel 360 can produce, for example, an audible noise and/or ahaptic sensation at each discrete increment through which the pawlportion 361 is rotated. In this manner, the user can hear and/or feelthe pawl portion 361 as it moves through each of the discreteincrements.

When the actuator 300 is in its second (i.e., disengaged) configuration(see FIG. 5), the pawl portion 361 is displaced from the ratchet wheel330 longitudinally by a distance d. As such, the second member 360 (andtherefore the stylet 304) can be rotated relative to the first member320 about the longitudinal axis L in either direction about thelongitudinal axis L (as indicated by arrows H and I). Moreover, therotation of the second member 360 relative to the first member 320 isnot resisted by the pawl portion 361 and/or the ratchet wheel 330. Inthis manner, the actuator 300 can be disengaged to allow the expandablemember 305 to be unfolded.

As described above, when the actuator 300 is in its first (i.e.,engaged) configuration, the amount of force required rotate the firstmember 320 is related to, among other things, the friction force betweenthe second retention surfaces 333, 364, the magnitude of the resultantforce F_(L), the magnitude of the force F_(R) and/or the magnitude ofthe force produced by the spring 354. Accordingly, the ease with whichthe first member 320 can be rotated can be controlled by adjusting theangle Θ, the surface finish of the second retention surfaces 333, 364,the force of spring 354, and the like.

As discussed above, the spring 354 is disposed such that one end of thespring 354 is engaged with the spring engagement portion 376 of thesecond member 360 and the other end of the spring is engaged with thespring shoulder 350 coupled to the first member 320. In this manner, thespring 354 acts to bias the actuator 300 in the engaged configuration.In use, the actuator 300 can be placed in its disengaged configurationby moving the second member 360 axially in a direction indicated byarrow G (see FIG. 5), thereby displacing the pawl portion 361 from theratchet wheel 330 by a distance d.

The force required to displace the pawl portion 361 from the ratchetwheel 330 and/or the distance d can be adjusted by changing the positionof the spring engagement portion 376, changing the position of thespring shoulder 350 and/or changing the spring constant associated withthe spring 354. In the illustrated embodiment, the spring shoulder 350is threadedly coupled to the first member 320, thereby allowing itsposition to be adjusted as desired. As illustrated in FIGS. 9 through11, the first member 320 includes a threaded portion 324 having a slot325 therethrough. The threaded portion 324 is configured to mate withthe threaded portion 351 of the spring shoulder 350 (see FIG. 18). Whenthe spring shoulder 350 is in the desired position, it is lockablycoupled to the first member 320 by inserting a pin 353 through a pinbore 352 such that a portion of the pin extends into the slot 325 (seeFIG. 8).

In addition to providing an engagement location for the spring 354, thespring shoulder 350 also acts in conjunction with the indicator 388 tolimit the rotation of the second member 360. The indicator 388 isthreadedly coupled to the first member 320 via mating threads 324 and390 (see FIG. 19). In contrast to the arrangement of the spring shoulder350, however, the indicator 388 is not lockably coupled to the firstmember 320, but is rather permitted to rotate freely along the threadedportion 324 of the first member 320. As shown in FIGS. 12, 13 and 19,the indicator 388 has four protrusions 389 configured to be received bythe corresponding slots 380 defined by the inner surface 379 of thehousing portion 372 of the second member 360. This arrangement allowsthe indicator 388 to move axially with respect to the second member 360,but prevents relative rotation between the indicator 388 and the secondmember 360. As such, when the second member 360 rotates relative to thefirst member 320, the indicator 388 rotates along the threaded portion324 of the first member 320, thereby moving in an axial directionrelative to the second member 360.

In use, when the expandable member 305 is in an untwisted configuration,the indicator 388 is positioned along the threaded portion 324 of thefirst member 320 such that it is in contact with a portion of theratchet wheel 330. When the second member 360 is rotated in a directioncorresponding to arrows E and H (in FIGS. 4 and 5, respectively), theindicator 388 travels axially along the threaded portion 324 of thefirst member 320 towards the spring shoulder 350. When the expandablemember 305 is in its fully twisted configuration, the indicator 388 isin contact with the spring shoulder 350. In this manner, rotation of thesecond member 360 beyond point at which the expandable member 305 is inits fully twisted configuration is prevented because the indicator 388cannot be moved further downward. Similarly, when the expandable member305 is in its untwisted configuration, the contact between the indicator388 and the ratchet wheel 330 prevents rotation in a directioncorresponding to arrow I (see FIG. 5), even when the twisting apparatusin its disengaged configuration. Said another way, the spring shoulder350 and the ratchet wheel 330 are positive stops limiting the rotationof the second member 360. In this manner, the actuator 300 can beconfigured to limit the number of turns through which the expandablemember 305 can be twisted, thereby preventing the expandable member 305from being over-twisted, which can potentially cause the expandablemember 305 to fail or become decoupled from the stylet 304 and/or thecatheter assembly 302. Similarly, the actuator 300 can be configured toprevent the expandable member 305 from being twisted in a directionopposite from that intended.

In some embodiments, the indicator 388 can provide an indication to auser of how many turns the second member 360 has undergone. In thismanner, the user can monitor the twisting of the expandable member 305to ensure that it is twisted a sufficient amount to facilitate removalvia a cannula without over-twisting, which can potentially cause theexpandable member 305 to fail or become decoupled from the stylet 304and/or the catheter assembly 302. In some embodiments, the housingportion 372 is constructed from a transparent material, such as a clearpolycarbonate, thereby allowing a user to visually determine how far theindicator has traveled. In other embodiments, the outer surface 378 ofthe housing portion 372 includes an indicia (not shown), such as aseries of graduated markings, thereby allowing a user to easilydetermine the number of rotations that the second member has traveled.In yet other embodiments, the indicator includes a marking configured tobe aligned with the corresponding markings on the housing portion 372.In yet other embodiments, the housing portion 372 includes a transparentwindow through which a user can view the indicator.

Although the indicator 388 is shown and described as being configured toprovide both a visual indication of the amount of rotation and apositive stop, in other embodiments, the indicator can be configured toprovide either a visual indication of the amount of rotation or act as apositive stop. In yet other embodiments, a twisting apparatus does notinclude an indicator.

As previously discussed, the distal end portion 326 of the first member320 is coupled to the catheter assembly 302 via coupler 314 such thatthe first member 320 cannot move relative to the catheter assembly 302.As shown in FIGS. 20 through 22, the coupler 314 has a first opening 315configured to matingly receive a portion of the luer cap 310 of thecatheter assembly 302. Similarly, the coupler 314 has a second opening316 configured to receive the distal end portion 326 of the firstmember. The second opening 316 further defines three slots 317configured to receive and mate with corresponding mounting tabs 328 onthe first member 320 (see FIGS. 9 through 11). In this manner, thecatheter assembly 302 and the actuator 300 can be keyed together suchthat the first member 320 cannot move relative to the catheter assembly302.

In some embodiments, the first member 320 is fixedly coupled to thecatheter assembly 302. For example, in some embodiments, the mountingtabs 328 are bonded into the slots 317 using known bonding techniques,such as an adhesive, a chemical bond, an RF weld or the like. In someembodiments, for example, the mounting tabs 328 are bonded into theslots 317 using a cyanoacrylate adhesive. In other embodiments, thefirst member can be removably coupled to the catheter, such as, forexample, by a threadedly coupling. In yet other embodiments, the firstmember can be removably coupled to the catheter via a quick-connectfitting. In this manner, the twisting apparatus can be used repeatedly.

Although the catheter and the twisting apparatus are shown and describedas being separate components, in some embodiments, the functionality ofthe twisting apparatus as described herein can be incorporated into asingle component. In other embodiments, certain functionality of thecatheter as described herein can be included in the twisting assemblyand vice versa.

As previously discussed, the second member 360 includes a pawl portion361 and a housing portion 372. As shown in FIGS. 12 through 17, the pawlportion 361 is a separate component that is configured to be fixedlycoupled to the proximal end portion 375 of the housing portion 372. Thepawl portion 361 includes four flange portions 367, each of whichincludes a mounting pin 366. The proximal end portion 375 of the housingportion 372 includes four corresponding recessed mounting areas 382,each of which includes a bore 365 configured to receive the mountingpins 366. In some embodiments, pins 366 are crush pins configured tohave an interference fit with the bores 365, thereby causing the pawlportion 361 to be fixedly coupled to the housing portion 372 whenpressed into place. In other embodiments, the pins can be bonded intotheir corresponding bores. In yet other embodiments, the pawl portion iscoupled to the housing portion without the aid of mating pins and bores.For example, in some embodiments, the pawl portion can be coupled to thehousing portion by laser welding, friction welding, adhesive bonding andthe like.

The components of the actuator 300 can be constructed from any materialhaving suitable biocompatibility, optical properties and/or mechanicalproperties. As described above, in some embodiments, portions of theactuator 300, such as, for example, the housing portion 372 can beconstructed from a clear polycarbonate. In other embodiments, portionsof the twisting apparatus, such as, for example, the first member 320and/or the second member 360 can be constructed from a polymer havinghigh toughness and/or high impact resistance to produce sufficient wearresistance of the teeth on the pawl portion 361 and/or the teeth on theratchet wheel 330. Examples of such materials include Nylon andacrylonitrile butadiene styrene (ABS).

Although the twisting apparatus is shown and described as allowingunidirectional rotation when in the engaged configuration, in otherembodiments a twisting apparatus can prevent any rotational motion whenin the engaged configuration. One such arrangement is illustrated inFIG. 24, which shows a portion of a pawl portion 2461 and a ratchetwheel 2430 according to an embodiment of the invention. As describedabove, both the ratchet wheel 2430 and the pawl portion 2461 include aset of teeth 2431 and 2462, respectively. The teeth 2431 on the ratchetwheel 2430 each include a first retention surface 2432 and a secondretention surface 2433. Similarly, the teeth 2462 on the pawl portion2461 each include a first retention surface 2463 configured to mate withthe first retention surface 2432 and a second retention surface 2464configured to mate with the second retention surface 2464. All of theretention surfaces 2432, 2433, 2463, 2464 are each substantiallyparallel to the longitudinal axis L_(A), thereby inhibiting motionnormal to the longitudinal axis L in a direction that brings theretention surfaces into contact with each other. As such, the pawlportion 2461 cannot move relative to the ratchet wheel 2430 in eitherthe direction as indicated by the arrow L or by the arrow M in FIG. 24when the pawl portion 2461 is engaged with the ratchet wheel 2430. Saidanother way, the rotational position of a portion of the twistingapparatus and therefore the stylet is locked when the twisting apparatusis in its engaged configuration.

Although the twisting apparatus is shown and described as having aratchet wheel having teeth disposed on an end face of the first memberand a corresponding pawl portion on the second member, in otherembodiments, the ratchet mechanism can be located in any suitableposition. One such arrangement is illustrated in FIGS. 25 and 26, whichshow a perspective exploded view and a cross-sectional view,respectively, of a portion of a twisting apparatus 2500 according to anembodiment of the invention. The twisting apparatus 2500 includes afirst member 2520 and a second member 2560 disposed about the firstmember 2520. The first member 2520 and second member 2560 are similar tothe first member 2320 and second member 2360 shown and described above.The first member 2520 differs, however, in that it includes a ratchetwheel 2530 disposed on a side surface 2522 of the first member 2520.Similarly, the second member 2560 includes a pawl portion 2561 disposedadjacent a side wall 2579 of the housing portion 2572 of the secondmember 2560. The second member 2560 includes a biasing member (notshown), such as a torsional spring, configured to maintain theengagement between the pawl portion 2561 and the ratchet wheel 2530. Asillustrated, the pawl portion 2561 includes an end portion 2569 thatextends through an opening 2578 in the side wall 2579 of the housingportion 2572. In this manner, a user can pivot the pawl portion 2561 inthe direction of the arrow marked N to place the twisting apparatus 2500in its disengaged configuration.

Although the actuators are shown and described as having a ratchet wheelwith a set of teeth and a corresponding pawl portion having a set ofteeth, in other embodiments, the ratchet wheel and/or the pawl portioncan include only a single detent mechanism. One such arrangement isillustrated in FIGS. 25 and 26, which show a twisting apparatus 2500including a second member 2560 having a pawl portion 2561 having asingle protrusion. Another such arrangement is illustrated in FIG. 27,which shows an exploded view of a twisting apparatus 2600 including afirst member 2620 and a second member 2660 disposed about the firstmember 2620. As described above, the first member 2620 defines a lumen2623 through which a portion of a stylet (not illustrated) can bedisposed such that the stylet can rotate about longitudinal axis Lrelative to the first member 2620. The side surface 2622 of the firstmember 2620 defines an opening 2670. The second member 2660, which isconfigured to engage an end portion of a stylet (not shown) as describedabove, includes a pawl portion 2661 disposed through an opening 2678 ina side wall 2679 of the second member 2660. The pawl portion 2661includes a first end portion 2669 that extends outside of the secondmember 2660, and a second end portion (not shown) disposed within thesecond member 2660 and configured to engage the opening 2670. The secondmember 2660 also includes a biasing member (not shown) configured tobias the pawl portion 2661 to engage the side surface 2622 of the firstmember 2620.

In use, when the second portion 2660 is rotated relative to the firstportion 2620, as indicated by the arrows marked P and Q, the pawlportion 2661 will engage the opening 2670 as the opening 2670 becomesaligned with the second end portion of the pawl portion 2661. Becausethe retention surfaces defined by the opening 2670 are substantiallyparallel to the longitudinal axis L, when the pawl portion 2661 isengaged with opening 2670, the second member 2660 is prevented fromrotating about the longitudinal axis L in either direction (as indicatedby the arrows P or Q). In this manner, the second member 2660 andtherefore the stylet can be rotated one turn at which point the pawlportion 2661 will engage the opening 2670 preventing further rotation.When additional rotation of the second member 2660 is desired, a usercan pivot the pawl portion 2661 in the direction of the arrow marked Rto overcome the force exerted by the biasing member and place thetwisting apparatus 2600 in its disengaged configuration, therebyallowing the second member 2660 to rotate relative to the first member2620.

In some embodiments, a twisting apparatus can include multiple ratchetwheels and/or pawl portions of the types shown and described above. Forexample, in some embodiments, a twisting apparatus can include a firstratchet mechanism configured to allow a portion (i.e., a second member)of the twisting apparatus to be rotated when engaged and a secondratchet mechanism configured to prevent rotation the portion whenengaged. In this arrangement, a portion of the twisting apparatus (i.e.,a second member) can be rotated over a certain angular distance, such asfor example, one turn, at which point the second ratchet mechanism canprevent further rotation. In this manner, a user can have greatercontrol over the rotation of a medical device. Said another way, oneratchet mechanism can control gross rotation and the other ratchetmechanism can control fine rotation.

Returning now to the actuator 300, FIG. 28 shows a front view of thestylet 304. As described above, the stylet 304 includes a distal endportion 307 and a proximal end portion 306. As described above, theengagement portion 308 at the proximal end portion 306 of the stylet 304is received by the actuator 300. This arrangement allows torque from theactuator 300 to be transmitted along the stylet 304 and to theexpandable member 305 such that at least a portion of the expandablemember 305 can be twisted about the stylet 304. Similarly, because theactuator 300 is coupled to the outer shaft 303, the outer shaft 303 isalso subject to torsional stress.

The ability of the outer shaft 303 and/or the stylet 304 to withstandthe torsional load applied by the actuator 300 can be characterized byan angle of twist φ and/or a shearing strain γ, as shown in FIG. 29.Although FIG. 29 shows only a portion of the stylet 304 for clarity,similar characteristics are applicable to the outer shaft 303 and/or anyother shaft, rod or elongate member that can be included within thecatheter assembly 302. The angle of twist φ of the stylet 304 is theangular displacement of the distal end portion 307 of the stylet 304relative to the proximal end portion 306 of the stylet 304, as measuredwithin a plane normal to the longitudinal axis LA (e.g., the endsurface), when the stylet 304 is subjected to a torsional load (shown byarrow TTT in FIG. 29). Similarly, the shearing strain γ of the stylet304 is the angular displacement of the distal end portion 307 of thestylet 304 relative to the proximal end portion 306 of the stylet 304,as measured in a surface parallel to the longitudinal axis LA, when thestylet 304 is subjected to the torsional load TTT. As the angle of twistand/or the shearing strain decreases, a structure is considered moretorsionally rigid.

In some embodiments, the stylet 304 is configured to have an angle oftwist φ between the proximal end portion 306 and the distal end portion307 of less than three hundred sixty degrees (i.e. one revolution) whenat least a portion of the expandable member 305 is twisted about thelongitudinal axis L of the stylet 304 through four revolutions. In otherembodiments, the stylet 304 is configured to have an angle of twist φbetween the proximal end portion 306 and the distal end portion 307 ofless than one hundred eighty degrees (i.e., a half revolution) when atleast a portion of the expandable member 305 is twisted about thelongitudinal axis L of the stylet 304 through four revolutions. In yetother embodiments, the stylet 304 is configured to have an angle oftwist φ between the proximal end portion 306 and the distal end portion307 of less than ninety degrees (i.e., a half revolution) when at leasta portion of the expandable member 305 is twisted about the longitudinalaxis L of the stylet 304 through four revolutions. In yet otherembodiments, the stylet 304 is configured to have an angle of twist φbetween the proximal end portion 306 and the distal end portion 307 ofless than sixty degrees (i.e., a half revolution) when at least aportion of the expandable member 305 is twisted about the longitudinalaxis L of the stylet 304 through four revolutions. In yet otherembodiments, the stylet 304 is configured to have an angle of twist φbetween the proximal end portion 306 and the distal end portion 307 ofless than thirty degrees (i.e., a half revolution) when at least aportion of the expandable member 305 is twisted about the longitudinalaxis L of the stylet 304 through four revolutions.

Similarly, in some embodiments, the outer shaft 303 is configured tohave an angle of twist φ between the proximal end portion 306 and thedistal end portion 307 of less than three hundred sixty degrees (i.e.one revolution) when at least a portion of the expandable member 305 istwisted about the longitudinal axis L of the stylet 304 through fourrevolutions. In other embodiments, the outer shaft 303 is configured tohave an angle of twist φ between the proximal end portion 306 and thedistal end portion 307 of less than one hundred eighty degrees (i.e., ahalf revolution) when at least a portion of the expandable member 305 istwisted about the longitudinal axis L of the stylet 304 through fourrevolutions. In yet other embodiments, the outer shaft 303 is configuredto have an angle of twist φ between the proximal end portion 306 and thedistal end portion 307 of less than ninety degrees (i.e., a halfrevolution) when at least a portion of the expandable member 305 istwisted about the longitudinal axis L of the stylet 304 through fourrevolutions. In yet other embodiments, the outer shaft 303 is configuredto have an angle of twist φ between the proximal end portion 306 and thedistal end portion 307 of less than sixty degrees (i.e., a halfrevolution) when at least a portion of the expandable member 305 istwisted about the longitudinal axis L of the stylet 304 through fourrevolutions. In yet other embodiments, the outer shaft 303 is configuredto have an angle of twist φ between the proximal end portion 306 and thedistal end portion 307 of less than thirty degrees (i.e., a halfrevolution) when at least a portion of the expandable member 305 istwisted about the longitudinal axis L of the stylet 304 through fourrevolutions.

Moreover, because the distal end portion 307 of the stylet 304 and theouter shaft 303 are inserted into the patient's body, compression and/orbuckling forces applied during insertion can also transmitted along thestylet 304 and/or the outer shaft 303. Other forces applied to thestylet 304 and/or the outer shaft 303 can include forces produced by theinflation pressure and/or forces produced as the expandable member 305is moved from the expanded configuration to the collapsed configuration(e.g., forces produced by applying a negative pressure to portions ofthe catheter assembly 302).

Accordingly, the stylet 304 and/or the outer shaft 303 can beconstructed from any material suitable for withstanding the forcesgenerated during the operation of the medical device 301. In someembodiments, for example, the stylet 304 and/or the outer shaft 303 canbe constructed from a biocompatible stainless steel having a hightensile strength and/or a high shear modulus. In other embodiments, thestylet 304 and/or the outer shaft 303 can be constructed from ahigh-strength polymer. In yet other embodiments, the stylet 304 and/orthe outer shaft 303 can be constructed from a composite material, suchas, for example, a polymer including reinforcing glass fibers.

Although composite materials, such as glass reinforced polymers, canoffer improved performance, the composite materials used to constructthe stylet 304 and/or the outer shaft 303 need not be limited to suchtraditional materials. For example, in some embodiments, the stylet 304and/or the outer shaft 303 can be constructed from extrudedbiocompatible polymers that are reinforced with nano-particles. Forexample, in some embodiments, the stylet 304 and/or the outer shaft canbe constructed from a blend of Nylon 12, one or more colorants andnano-particle fillers. Nano-particles can include any inorganic mineralhaving a high aspect ratio (i.e., a length to width ratio ofapproximately between 300:1 and 1500:1) with at least one dimensionhaving a size in the nanometer range. In some embodiments, for example,nano-particles can include hydrotalcite, montmorillonite and/or micafluoride.

Because nano-particles have a size that approximates the size of thepolymer molecules, the nano-particles can interact with the polymer atthe molecular level, which can immobilize portions of the polymer chain.Such immobilization can lead to significant improvements in strength,hardness and/or chemical resistance. In some embodiments, thenano-particles can be combined with a cross-linking agent, such as, forexample, trallylisocyanumrate, to promote such molecular interaction. Insome embodiments, the mixture of nano-particles and the cross-linkingagent can be exposed to irradiation to promote such molecularinteraction.

Although the cross-sections of the stylet 304 and the outer shaft 303are shown and described as being circular, in some embodiments, thecross-section of the stylet 304 and/or the outer shaft 303 can be of anysuitable shape. For example, in some embodiments, the cross-section ofthe stylet 304 and/or the outer shaft 303 can have a rectangular shape.Such non-circular shapes can improve mechanical characteristics of thestylet 304 and/or the outer shaft 303, such as, for example, the columnstrength, the resistance to bending and/or the resistance to bending intorsion. Said another way, the cross-sectional shape of the stylet 304and/or the outer shaft 303 can be selected to have a large shearmodulus, thereby increasing the resistance to angular deflection.

Although the first member 320 of the actuator 300 is shown in FIGS. 4and 5 and described above as being fixedly coupled catheter assembly302, in some embodiments, the first member can be coupled to thecatheter assembly in a manner that allows longitudinal movement betweenthe first member and the catheter assembly. For example, FIGS. 30-34show a portion of a twisting apparatus 1200 according to an embodimentof the invention in which a first member 1220 is coupleable to acatheter assembly (not shown in FIGS. 30-34) such that the first member1220 can move longitudinally relative to the catheter assembly. In thismanner, when a rotational force is applied to a second member 1260, theresultant longitudinal force produced by the angled surfaces of a pawlportion 1261 and a ratchet wheel 1230 causes the second member 1260 tomove proximally and the first member 1220 to move distally. In someembodiments, the longitudinal movement of the first member 1220 canresult in a twisting mechanism 1200 in which the mating teeth on theratchet wheel 1230 and pawl portion 1261 engage each other consistentlyregardless of the number of turns through which the pawl portion 1261has been twisted. Said another way, by allowing longitudinal movement ofthe first member 1220, the mating teeth on the ratchet wheel 1230 andthe pawl portion 1261 can be less likely to slip when in the engagedconfiguration.

In the illustrated twisting apparatus 1200, the second member 1260 isdisposed about the first member 1220. The first member 1220 includes adistal end portion 1226 and a proximal end portion 1227. As describedabove, the proximal end portion 1227 of the first member 1220 includes aratchet wheel 1230 removably engagable with a pawl portion 1261 of thesecond member 1260. The second member 1260 includes a housing portion1272 and the pawl portion 1261 that is removably engagable with theratchet wheel 1230 of the first member 1220. The pawl portion 1261 ofthe second member 1260 is fixedly coupled to the housing portion 1272.The pawl portion 1261 includes an extension portion 1291 that defines anopening 1281 within which a portion of a stylet (not shown in FIGS.30-34) is received. As described above, the opening 1281 has a long,narrow shape such that when the second member 1260 rotates, the styletwill engage the sides of the opening 1281 thereby causing the stylet torotate with the second member 1260. Moreover, because the stylet is notfixedly coupled to the second member 1260, the second member 1260 canmove axially relative to the stylet and/or the first member 1220.

In contrast to the actuator 300 shown and described above, the distalend portion 1226 of the first member 1220 can be movably coupled to acatheter assembly via coupler 1214, such that the first member 1220 canmove longitudinally relative to the catheter assembly. Similar to thecoupler 314 described above, the coupler 1214 has a first opening 1215configured to matingly receive a portion of a luer cap 1210 of thecatheter assembly (not shown in FIGS. 30-34). The coupler 1214 definesfour openings 1213 through which two connecting pins 1292 (only one pinof the four pins is shown in FIGS. 31 and 32) can be disposed. Each pin1292 is disposed within a corresponding pair of openings 1213 such thatthe distal end portion 1298 of the luer cap 1210 is spaced apart fromthe pins 1292 by a distance d, as shown in FIG. 31. In this manner, thecoupler 1214 (and therefore, the first member 1220) can movelongitudinally relative to the luer cap 1210 by the distance d.

As shown in FIGS. 33 and 34, the extension portion 1291 of the pawlportion 1261 extends above the proximal surface of the pawl portion1261. In this manner, the longitudinal length of the opening 1281 can beincreased to allow a greater amount longitudinal movement of the stylet(not shown in FIGS. 33 and 34) within the opening. In other embodiments,an extension portion of the pawl portion can extend distally into thelumen defined by the first member 1220 of the twisting apparatus 1200.

Although the pins 1292 are shown as being disposed within the openings1213 such that the distal end portion 1298 of the luer cap 1210 isspaced apart from the pin 1292 by a distance d, in other embodiments,the pins 1292 can be disposed within the openings 1213 such thatsubstantially no space exists between the distal end portion 1298 of theluer cap 1210 and the pins 1213. In such embodiments, the connectingpins 1292 can be constructed from a flexible material, such as, forexample, stainless steel spring wire, to allow the connecting pins 1292to bend when the coupler 1214 (and therefore, the first member 1220) ismoved longitudinally relative to the luer cap 1210. In this manner, whena longitudinal force, such as, for example, the resultant force producedwhen the twisting apparatus 1200 is rotated, is applied to the firstmember 1220 of the twisting apparatus 1200, the first member 1220 canmove longitudinally relative to the catheter assembly.

The range of motion of the first member 1220 relative to the catheterassembly and/or the force used to move the first member 1220 relative tothe catheter assembly is a function of the distance d between theconnecting pins 1292 and the luer cap 1210 and the flexibility of theconnecting pins 1292. In some embodiments, for example, the connectingpins 1292 can be configured to allow the first member 1220 to moveapproximately a distance corresponding to the height of the teeth on theratchet wheel and pawl. In some embodiments, for example, the openings1213 and connecting pins 1292 can be configured to allow the firstmember 1220 to move between 1 and 3 mm relative to the catheterassembly. In other embodiments, for example, the openings 1213 andconnecting pins 1292 can be configured to allow the first member 1220 tomove a distance greater than the height of the teeth on the ratchetwheel and pawl.

Although the coupler 1214 is shown and described as being movablycoupled to the luer cap via connecting pins 1292 that can be flexible,in other embodiments, the connecting pins need not be flexible. Forexample, in some embodiments, a coupler can include slotted openingsthrough which rigid pins are disposed to connect the coupler to the luercap. In such an arrangement the rigid pins can be coupled to the luercap, for example, by being press fit into an opening defined by the luercap, thereby allowing the coupler to move relative to the luer cap asthe slotted openings move about the rigid pins. In other embodiments,the rigid pins can be fixedly coupled to the coupler and the luer capcan include corresponding slotted openings, within which the pins canmove.

Although the twisting apparatus 1200 is shown and described above asallowing relative motion between the first member 1220 and a catheterassembly via motion of the coupler with respect to the luer cap, inother embodiments, any suitable mechanism for permitting longitudinalmotion between the first member and a catheter assembly can be employed.For example, FIGS. 35-38 show a twisting mechanism 1300 having a firstmember 1320 that is movably coupled to a coupler 1314.

Similar to the twisting apparatuses shown and described above, theillustrated twisting apparatus 1300 includes a first member 1320 and asecond member 1360 disposed about the first member 1320. The secondmember 1360 includes a housing portion 1372 and the pawl portion 1361that is removably engagable with the ratchet wheel 1330 of the firstmember 1320. The pawl portion 1361 of the second member 1360 is fixedlycoupled to the housing portion 1372. The pawl portion 1361 includes anextension portion 1391 that defines an opening 1381 within which aportion of a stylet (not shown in FIGS. 35-38) is received.

The first member 1320 includes a distal end portion 1326 and a proximalend portion 1327. As described above, the proximal end portion 1327 ofthe first member 1320 includes a ratchet wheel 1330 removably engagablewith a pawl portion 1361 of the second member 1360. As described in moredetail herein, the distal end portion 1326 is movably coupled to thecoupler 1314, which is fixedly coupled to a catheter assembly (not shownin FIGS. 35-38). In this manner, the first member 1320 can movelongitudinally relative to the catheter assembly.

In use, when the twisting apparatus 1300 is in its first (e.g., engaged)configuration (see FIGS. 35 and 38), the second member 1360 can berotated relative to the first member 1320 about the longitudinal axis Lin a direction as indicated by arrow P in FIG. 36. As described above,the rotational force applied to the pawl portion 1361 produces aresultant force F_(L1) that acts on the second member 1360 and an equaland opposite resultant force F_(L2) that acts on the first member 1320portion parallel to the longitudinal axis L and in the proximaldirection. The resultant forces F_(L1) and F_(L2) cause the pawl portion1361 to move proximally and/or the first member 1320 to move distally,as shown in FIG. 36. In this manner, the pawl portion 1361 can berotated relative to the ratchet wheel 1330 in the direction P in aunidirectional, controlled and/or incremental fashion, as describedabove.

The distal end portion 1326 of the first member 1320 includes twoflatted portions 1393. The coupler 1314 includes corresponding flattedportions 1394 within the opening 1316. This arrangement preventsrelative rotation between the first member 1320 and the coupler 1314.Similarly, the coupler 1314 includes multiple retention tabs 1396 thatengage a retention lip 1395 on the distal end portion 1326 of the firstmember 1320 (see FIG. 35). In this manner, the range of motion of thefirst member 1320 relative to the catheter assembly can be limited.

Other aspects of the invention include various configurations of theexpandable member. Various methods for improving the structuralintegrity of expandable member are also disclosed herein. Details of theexpandable member 305 are now discussed with reference to FIG. 39. FIG.39 is a perspective view of the expandable member 305 in its expandedconfiguration. The expandable member 305 includes a distal taperedportion 336, a proximal tapered portion 335 and a central portion 334disposed between the distal tapered portion 336 and the proximal taperedportion 335. The proximal tapered portion 335 terminates in a proximalbond portion 339 that is coupled to the outer shaft 303. Similarly, thedistal tapered portion 336 terminates in a distal bond portion 338 thatis coupled to the distal end portion 307 of the stylet 304.

The central portion 334 of the expandable member 305 is substantiallycylindrical in shape and has a diameter D1 and a length L1. The distaltapered portion 336 and the proximal tapered portion 335 are eachsubstantially conical in shape. The total volume of the expandablemember 305 when in the expanded configuration is a function of thediameter D1, the length L1 and the configuration of the tapered portions336, 335. In some embodiments, the diameter D1 can be between 8 mm and20 mm (0.315 in. and 0.787 in.). In other embodiments, the diameter D1can be between 8 mm and 13 mm (0.315 in. and 0.512 in.). In yet otherembodiments, the diameter D1 can be approximately 12 mm (0.472 in.).Similarly, in some embodiments, the length L1 can be up to 30 mm (1.181in.). In other embodiments, the length L1 can be approximately 22 mm(0.866 in.). The volume of the expandable member 305 when in theexpanded configuration can range from 0.5 cubic centimeters to 10 cubiccentimeters. In some embodiments, the volume of the expandable member305 when in the expanded configuration is approximately 3.5 cubiccentimeters.

Although shown as having a substantially cylindrical shape, in someembodiments, the expandable member 305 can be configured to assume anysuitable shape and/or size when in the expanded configuration. Forexample, in some embodiments, an expandable member can have a shape thatapproximates the inner shape of the bone structure in which it is to bedeployed, as described in U.S. Pat. No. 6,981,981 and incorporatedherein by reference in its entirety. In other embodiments, an expandablemember can have various portions each of which has a different shape,thereby resulting in an expandable member having a discontinuous shape.In yet other embodiments, an expandable member can have an asymmetricalshape, such as, for example, a kidney bean shape, an asymmetrical ringshape or the like.

Although the catheter assembly 302 is shown and described above asincluding a stylet 304 disposed within an outer shaft 309 wherein thedistal end 307 of the stylet 304 is coupled to the distal bond portion338 of the expandable member 305, in some embodiments, a catheter caninclude any number of shafts, tubes and/or other components. Forexample, FIG. 40 shows a portion of a catheter assembly 1002 having anouter shaft 1003 and an inner shaft 1011 according to an embodiment ofthe invention. The outer shaft 1003 defines a lumen through which aportion of the inner shaft 1011 is rotatably disposed. Similarly, theinner shaft 1011 defines a lumen through which a portion of a stylet1004 is disposed. In some embodiments, the inner shaft 1011 can beconstructed from similar materials from which the outer shaft 1003and/or the stylet 1004 are constructed. In some embodiments, forexample, the inner shaft can be constructed from Nylon 12.

The catheter assembly 1002 includes an expandable member 1005 of thetype shown and described herein. A proximal bond portion 1039 of theexpandable member 1005 is coupled to the outer shaft 1003 over adistance X_(P) to form a fluid-tight seal. Similarly, a distal bondportion 1038 of the expandable member 1005 is coupled to a distalportion 1012 of the inner shaft 1011 over a distance X_(D) to form afluid-tight seal. The distal portion 1012 of the inner shaft 1011 iscoupled to the distal end portion 1007 of the stylet 1004 over adistance X_(S). In this manner, the distal bond portion 1038 of theexpandable member 1005, the inner shaft 1011 and the stylet 1004 arejoined together to form a fluid-tight seal. As used herein, the term“fluid-tight seal” refers to a seal that substantially prevents a liquidand/or a gas from passing therethrough. For example, in someembodiments, a fluid-tight seal can prevent a liquid inflation medium,such as saline, from passing therethrough, while allowing a gas to passtherethrough. In other embodiments, a fluid-tight seal can prevent botha liquid and a gas from passing therethrough.

As previously discussed, in some embodiments, the catheter assembly 1002includes an actuator (not shown in FIG. 40) to twist at least a portionof the expandable member 1005 about the stylet 1004. In this manner, aprofile (e.g., the outer diameter) of the expandable member 1005 can beminimized when the expandable member 1005 is in its collapsedconfiguration (see e.g., FIG. 42) to facilitate insertion and/or removalof the expandable member 1005 via a cannula. Accordingly, as describedabove, the components of the catheter assembly 1005, including theregions where the expandable member 1005 is coupled to the outer shaft1003 and/or the inner shaft 1011, can be subject to torsional loadtransmitted by the actuator.

In some embodiments, for example, the proximal bond portion 1039 of theexpandable member 1005 is coupled to the outer shaft 1003 such that theproximal bond portion 1039 does not rotate relative to the distal endportion of the outer shaft 1003 (e.g., the proximal bond portion 1039remains securely coupled to the outer shaft 10030) when at least aportion of the expandable member 1005 is twisted about the inner shaft1011 and/or the stylet 1004 through at least four revolutions. In someembodiments, the proximal bond portion 1039 of the expandable member1005 is coupled to the outer shaft 1003 such that a fluid-tight seal ismaintained between the proximal bond portion 1039 and the distal endportion of the outer shaft 1003 when at least a portion of theexpandable member 1005 is twisted about the inner shaft 1011 and/or thestylet 1004 through at least four revolutions. In other embodiments, theproximal bond portion 1039 of the expandable member 1005 is coupled tothe outer shaft 1003 such that a fluid-tight seal is maintained betweenthe proximal bond portion 1039 and the distal end portion of the outershaft 1003 when at least a portion of the expandable member 1005 istwisted about the inner shaft 1011 and/or the stylet 1004 through atleast six revolutions.

Similarly, in some embodiments, the distal bond portion 1038 of theexpandable member 1005 is coupled to the distal portion 1012 of theinner shaft 1011 such that the distal bond portion 1038 does not rotaterelative to the distal portion 1012 of the inner shaft 1011 when atleast the portion of the expandable member 1005 is twisted about theinner shaft 1011 and/or the stylet 1004 through at least fourrevolutions. In some embodiments, the distal bond portion 1038 of theexpandable member 1005 is coupled to the distal portion 1012 of theinner shaft 1011 such that a fluid-tight seal is maintained between thedistal bond portion 1038 and the distal portion 1012 of the inner shaft1011 when at least the portion of the expandable member 1005 is twistedabout the inner shaft 1011 and/or the stylet 1004 through at least fourrevolutions. In other embodiments, the distal bond portion 1038 of theexpandable member 1005 is coupled to the distal portion 1012 of theinner shaft 1011 such that a fluid-tight seal is maintained between thedistal bond portion 1038 and the distal portion 1012 of the inner shaft1011 when at least the portion of the expandable member 1005 is twistedabout the inner shaft 1011 and/or the stylet 1004 through at least sixrevolutions.

The strength of the coupling between the expandable member 1005 and theouter shaft 1003 and/or the inner shaft 1011 is dependent on a widerange of parameters, which can include the manufacturing processes usedto coupled the expandable member 1005 to the outer shaft 1003 and/or theinner shaft 1011, the material properties of the components beingcoupled and/or the axial length of the coupling (X_(P) and X_(D)). Insome embodiments, the greater the axial length of the coupling, thegreater the strength (i.e., ability to withstand torsional stress) ofthe coupling. In some embodiments, however, the axial length of thecoupling (X_(P) and X_(D)) is minimized to increase the length that thecentral portion of the expandable member (see e.g., central portion 334in FIG. 39) can extend into a bone structure. Accordingly, as describedherein, the axial length of the coupling (X_(P) and X_(D)) and themanufacturing processes used to couple the expandable member to theinner shaft and/or the outer shaft can be selected to provide thedesired strength with the shortest possible axial length (X_(P) andX_(D)).

In some embodiments, for example, the distance X_(P) can be between 1 mmand 7 mm (0.040 in. and 0.275 in.). In other embodiments, the distanceX_(P) can be approximately 2.5 mm (0.100 in.). Similarly, in someembodiments, the distance X_(D) can be between 1 mm and 5 mm (0.040 in.and 0.200 in.). In other embodiments, the distance X_(D) can beapproximately 3 mm (0.118 in.). In yet other embodiments, the distanceX_(D) can be approximately 2 mm (0.080 in.). Similarly, in someembodiments, the distance X_(S) can be between 5 mm and 38 mm (0.200 in.and 1.5 in.). In other embodiments, the distance X_(S) can correspondapproximately to the length of the expandable member 1005. In yet otherembodiments, the inner shaft 1011 can be coupled to the stylet 1004 atseveral longitudinal locations. In yet other embodiments, the innershaft 1011 can be coupled to the stylet 1004 along the entire length ofthe inner shaft 1011. Said another way, in some embodiments, the innershaft 1011 can be coupled to the stylet 1004 along the entire length ofthe inner shaft 1011, thereby forming a composite member configured tobe coupled to the expandable member 1005 and transmit the torsionalforces produced by a twisting apparatus of the type shown and describedabove.

In some embodiments, the stylet 1004, the inner shaft 1011 and thedistal bond portion 1038 of the expandable member 1005 can be coupledtogether in a single manufacturing operation. In other embodiments, thestylet 1004 and the inner shaft 1011 can be coupled together in a firstoperation, and the distal bond portion 1038 of the expandable member1005 and the distal portion 1012 of the inner shaft 1011 can be coupledtogether in a second operation. For example, in some embodiments, thestylet 1004 and the inner shaft 1011 can be coupled together using aradio frequency induction heating process (i.e., an RF bonding process)and the distal bond portion 1038 of the expandable member 1005 and thedistal portion 1012 of the inner shaft 1011 can be coupled togetherusing a laser bond process. The RF bonding process and the laser bondprocess are described in more detail herein.

In some embodiments, the proximal end portion of the inner shaft 1011(not shown in FIG. 40) can be retained within a Y-connector of acatheter assembly, similar to the Y-connector 309 shown and describedabove with reference to FIG. 6. In this manner, the Y-connector can actas an interface for the outer shaft, the inner shaft, the inflationdevice and/or the twisting apparatus. In some embodiments, the proximalend portion of the inner shaft 1011 can be retained within theY-connector such that the inner shaft 1011 rotates with the stylet 1004relative to the outer shaft 1003 and/or the Y-connector. In otherembodiments, the proximal end portion of the inner shaft 1011 can beretained within the Y-connector such that the proximal end portion ofthe inner shaft 1011 does not rotate with the stylet 1004. In yet otherembodiments, as described above, a catheter assembly includes only oneof a stylet or an inner shaft.

Although the catheter 1002 is shown and described as including a stylet1004, an inner shaft 1011 and an outer shaft 1003, in other embodiments,a catheter can include any number of shafts, tubes and/or stylets. Forexample, FIG. 41 shows a portion of a catheter 1102 having an outershaft 1103, an inner shaft 1111, a stylet 1104 and a sleeve 1197according to an embodiment of the invention. Similar to the catheter1002 described above, the outer shaft 1103 defines a lumen through whicha portion of the inner shaft 1111 is rotatably disposed. The inner shaft1111 defines a lumen through which at least a portion of a stylet 1104is disposed. The catheter 1102 differs from the catheter 1002, however,in that catheter 1102 includes a sleeve 1197 disposed between theexpandable member 1105 and the inner shaft 1111 along the distal endportion 1112 of the inner shaft 1111. In some embodiments, the sleeve1197 can be constructed from a polymer, such as PEBAX®, configured toenhance the strength of the distal bond (e.g., the bond between theexpandable member 1105 and the inner shaft 1111). As described herein,in some embodiments, the expandable member 1105, the inner shaft 1111and the sleeve 1197 can be collectively coupled (e.g., coupled in oneprocess such that there is not a first coupling between the inner shaft1111 and the sleeve 1197 and a second coupling between the sleeve 1197and the expandable member 1105 that is separate and distinct from thefirst coupling).

In some embodiments, the sleeve 1197 can include a colorant foridentification purposes and/or to be excited by a laser used to couplethe expandable member 1105, the inner shaft 1111 and the sleeve 1197.For example, in some embodiments, the sleeve 1197 can be constructedfrom a polymer that includes two percent purple resin.

Although the catheters shown and described above include a stylet, insome embodiments, a catheter do not include a stylet. For example, insome embodiments, a catheter can include an outer shaft and an innershaft of the type described above. In such embodiments, for example, theinner shaft can engage a twisting apparatus configured to rotate theinner shaft relative to the outer shaft, thereby causing the expandablemember to be twisted, as described above.

FIG. 42 shows the expandable member 305 in its collapsed configuration,with the expandable member being wrapped about the stylet 304. Theexpandable member 305 includes multiple pleats 340 disposedlongitudinally along the central portion 334. As shown in FIGS. 43 and44, the pleats 340 can be folded and/or wrapped circumferentially aboutthe longitudinal axis La of the stylet 304, as indicated by the arrow Lin FIG. 43, to minimize the profile (e.g., the outer diameter) of theexpandable member 305 when in its collapsed configuration. In thismanner, the expandable member 305 can be inserted and/or removed via acannula. The formation of the pleats is discussed in more detail herein.

Although the expandable member 305 is shown and described as havingpleats 340 along the central portion 334, in some embodiments the pleats340 can extend along the proximal tapered portion 335 and/or the distaltapered portion 336. Similarly, the pleats 340 can be of any suitablesize and/or shape. For example, in some embodiments, the pleats 340 canbe non-linear. In other embodiments, the pleats 340 can beasymmetrically disposed about the central portion 334 of the expandablemember 305. In yet other embodiments, an expandable member can includeany number of pleats, such as three, four, five, six or more pleats.

Although the pleats 340 are shown and described as being folded and/orwrapped about the longitudinal axis of the stylet 304, in otherembodiments, the pleats 340 can be folded and/or wrapped about anysuitable axis. For example, FIG. 45 is a cross-sectional view of anexpandable member 405 according to an embodiment of the invention havingpleats 440 that are folded in an accordion-like fashion about an axisnormal to the longitudinal axis La of the stylet 404. In someembodiments, an expandable member can include pleats that are folded inmultiple directions about multiple axes. For example, in someembodiments, an expandable member can include some pleats that arefolded in an accordion-like fashion, similar to that shown in FIG. 45,and some pleats that are also wrapped about the longitudinal axis of thestylet, similar to that shown in FIG. 43.

Returning to FIGS. 39-44, the expandable members shown and describedherein can be constructed from any material having suitable propertiesfor being inserted percutaneously into a bone structure, compacting bonematerial and/or displacing bone material. Such material properties caninclude, for example, biocompatibility, resistance to corrosion and/ordegradation, high tensile strength, high tear resistance, high punctureresistance, high lubricity, suitable hardness, compliance (e.g., theexpandable member's ability to expand appreciably beyond its nominalsize) and/or elasticity. Moreover, the material properties suitable foroperation within a bone structure can be different than the materialproperties that may be suitable for expandable members operating inother regions of a patient's body. Said another way, an expandablemember suitable for use in the cardiovascular system may not be suitablefor use in bone structures because of the nature of such bonestructures, which can include multiple regions of bone having differentdensities, sharp protrusions, narrow access channels and the like, andbecause of the intended operation of the expandable member within thebone structure, which can include compacting bone and/or displacingbone.

In some embodiments, for example, an expandable member can be ahigh-compliant balloon configured to significantly elastically deformwhen expanded. In other embodiments, an expandable member can be alow-compliant balloon configured to compact and/or displace bonematerial without significantly deforming. The compliance of a balloon isthe degree to which a size of the balloon in an unfolded state changesas a function of the pressure within the balloon. For example, in someembodiments, the compliance of a balloon can be used to characterize thechange in the diameter of the unfolded balloon as a function of theballoon pressure. In some embodiments, the diameter of an unfoldedballoon characterized as a low-compliant balloon can change by zero toten percent over the range of inflation pressure. In other embodiments,an unfolded balloon in which the diameter changes by as much as 20percent may be characterized as a low-compliant balloon. Similarly, insome embodiments, the diameter of an unfolded balloon characterized as ahigh-compliant balloon can change by 18 to 30 percent. In otherembodiments, the diameter of an unfolded high-compliant balloon canchange by as much as 100 to 600 percent over the range of inflation.

In some embodiments, the compliance of a balloon can be used tocharacterize the change in the length of the balloon as a function ofthe balloon pressure. The change in length can also be referred to asthe elongation percentage of the balloon. In other embodiments, thecompliance of a balloon can be used to characterized the change involume of the balloon as a function of the balloon pressure. Similarly,in some embodiments, the compliance of a balloon can be used tocharacterize the material properties from which the balloon or portionsof the balloon are constructed.

In some embodiments, for example, an expandable member can beconstructed from a low-compliant material (e.g., a material having a lowmodulus of elasticity), such as polyamide, polyethylene terephthalate(PET), Nylons, cross-linked Polyethylene, PEBAX®, Polyurethanes, PVC orany blend of these compounds. In some embodiments, an expandable membercan be constructed from Nylon 12.

Because the overall characteristics of the expandable member, includingthe compliance, can be a function of both the material from which theexpandable member is constructed and the structural characteristics ofthe expandable member, the material from which the expandable member 305is constructed can be selected in conjunction with the desiredstructural characteristics of the expandable member. As discussed above,the overall characteristics of an expandable member to be deployedwithin a bone structure can be different than the characteristics thatmay be suitable for expandable members operating in other regions of apatient's body. For example, an expandable member used to displace abone structure may be configured to exert a much higher lifting forcewhen expanded than an expandable member used to deploy a stent.Similarly, an expandable member used to repair a fracture that occurred,for example, three months before treatment may be configured to exert ahigher lifting force than an expandable member used to repair a newfracture. Similarly, an expandable member used to repair a fracture thatoccurred, for example, six months or more before treatment may beconfigured to exert a higher lifting force than an expandable memberused to repair a new fracture.

In some embodiments, the performance characteristics of the expandablemember 305, such as the burst pressure, the lifting force when theexpandable member 305 is being expanded (e.g., the dynamic loadcapability) and/or the static load capability when expanded, can be afunction of the tensile strength, the compliance of the material, thethickness of the material and/or the inclusion of any stressconcentration risers (i.e., discontinuous surfaces and the like).Accordingly, in some embodiments, an expandable member can beconstructed of a material having a very high tensile strength to offsetthe effects of stress concentration risers. In other embodiments, asdiscussed in more detail herein, an expandable member can include areasof reinforcement, such as for example, a coating, an abrasion-resistantfiller, such as carbon or PEBAX®, within the primary layer and/or outerlayer to produce the desired characteristics.

In some embodiments, for example, an expandable member can have a ratedburst pressure of between 1.4 MPa and 2.8 MPa (200 psi and 400 psi). Therated burst pressure is the pressure to which a statistical sampling ofexpandable members can be inflated without failure. For example, therated burst pressure can be associated with a 99 percent compliance witha statistical confidence of 95 percent. Said another way, the ratedburst pressure is not the maximum pressure to which the expandablemember can be inflated, but is a pressure level below which theexpandable member will not likely fail. In other embodiments, theexpandable member can have a rated burst pressure of as much as 5.5 MPa(800 psi). In yet other embodiments, the expandable member can have arated burst pressure of approximately 2.4 MPa (350 psi). Similarly, insome embodiments, the expandable member 305 can be configured to have astatic load capability, which can be an indication of the force that canbe exerted when displacing bone, of between 0.25 MPa and 4 MPa (36 psiand 580 psi). In yet other embodiments the expandable member 305 can beconfigured to have a static load capability of approximately 3 MPa (435psi).

Although the expandable member 305 is shown and described as beingconstructed from a single material, in some embodiments, an expandablemember can be constructed from more than one material. In this manner,the expandable member can use the advantageous properties of multiplematerials. For example, FIG. 46 is a cross-sectional view of anexpandable member 505 according to an embodiment of the invention thatis constructed of two different materials. As described above, theexpandable member 505 includes a distal tapered portion 536, a proximaltapered portion 535 and a central portion 534 disposed between thedistal tapered portion 536 and the proximal tapered portion 535. Theproximal tapered portion 535 terminates in a proximal bond portion 539that is coupled to the outer shaft 503. Similarly, the distal taperedportion 536 terminates in a distal bond portion 538 that is coupled tothe distal end portion 507 of the stylet 504.

The expandable member 505 has an inner layer 542 disposed within anouter layer or sheath 543. The inner layer 542 is constructed from afirst material and the outer sheath 543 is constructed from a secondmaterial, different than the first material. In some embodiments, theinner layer 542 can be constructed from a high strength, low-compliantmaterial, such as, for example Nylon 12. Such low-compliant materials,however, can have a crystalline or semi-crystalline molecular structure,which can result in decreased abrasion resistance, decreased tearresistance and/or decreased puncture resistance. Moreover, to minimizethe profile of the expandable member 505, the wall of the inner layer542 can be relatively thin, which can further decrease the abrasionresistance, tear resistance and/or puncture resistance. Accordingly, theouter sheath 543 can be constructed from a polymer having a moreamorphous molecular structure, thereby providing increased abrasionresistance, tear resistance and/or puncture resistance.

The ability of the outer sheath 543 to resist surface abrasion, tearing,and puncture when deployed within a bone structure can be characterizedin various ways. For example, a Taber Abrasion Resistance Value of lessthan about 90 mg loss can indicate a sufficient level of resistance topuncture when the outer sheath 543 is in contact with bone. Similarly, aRotating Drum Abrasion Resistance Value of less than 70 mm³ can alsoindicate a sufficient resistance to puncture when contacting bone. Thetear resistance of the outer sheath 543 can be characterized by theElmendorf tear strength, which is a measure of the force required topropagate an existing slit a fixed distance to the edge of the testsample. In some embodiments, an Elmendorf tear strength of greater thanabout 280 lbf/in can indicate a sufficient resistance to tearing causedby bone abrasion. In other embodiments, the abrasion resistance, tearresistance and/or puncture resistance can be characterized by the ShoreHardness value of the outer sheath 543.

In yet other embodiments, the puncture and/or abrasion resistance of theexpandable member 505 and/or the outer sheath 543 can be measured bydetermining the force required to puncture the expandable member 505and/or outer sheath 543. In certain instances, for example, such a testcan include placing a sample of the expandable member 505 and/or outersheath 543 on a test bed while retaining the edges thereof. A test toolconstructed from a predetermined material (e.g., stainless steel) andhaving a predetermined geometry (i.e., the tip geometry) is then loweredat a constant speed until the tip contacts the test specimen. The forcerequired to puncture the expandable member 505 and/or outer sheath 543is then determined by a load cell coupled to the test tool. The forcecan be used, for example, as a means to compare various materials, sizesand/or coatings from which expandable members are constructed. In someembodiments, an expandable member 505 and/or outer sheath 543 can have apuncture force according to the above-described test of 12 lbf.

Because polymers having a lesser degree of crystallinity can have adifferent level of compliance than the low-compliant materials fromwhich the inner layer 542 can be constructed, the size of the outersheath 543 can be selected in conjunction with the expansion ratio(i.e., a radial and a longitudinal elongation percentage) of thematerial from which the outer sheath 543 is constructed. In this manner,the outer sheath 543 can be selected to ensure that when the expandablemember 505 is in the expanded configuration, the outer sheath 543 doesnot burst, limit the expansion of the inner layer 542 or the like. Forexample, in some embodiments, the inner layer 542 can be constructedfrom a low-compliant material such that a size of the inner layer 542(e.g. the diameter when unfolded) changes by between zero and twentypercent and the outer sheath 543 can be constructed from a morecompliant material such that a size of the outer sheath 543 (e.g. thediameter when unfolded) changes by approximately fifty percent. In otherembodiments, the inner layer 542 can be constructed from a low-compliantmaterial such that an unfolded size of the inner layer 542 changes byapproximately ten to twenty percent and the outer sheath 543 can beconstructed from a high-compliant material such that an unfolded size ofthe outer sheath 543 changes by approximately between 400 and 600percent. In yet other embodiments, the inner layer 542 can be fabricatedof a high-compliant material such that an unfolded size of the innerlayer 542 changes by approximately 200 to 400 percent and the outersheath 543 can be fabricated of a high-compliant material such that anunfolded size of the outer sheath 543 changes by approximately between400 and 600 percent.

In some embodiments, the outer sheath 543 can be constructed from amaterial having a high lubricity, which can be beneficial duringinsertion and/or removal of the expandable member. During expansion, thelubricity of the outer sheath 543 can also prevent the folds and/orpleats of material from adhering together, thereby ensuring properexpansion. Similarly, the lubricity of the outer sheath 543 can alsoimprove the tear resistance of the expandable member 505 by allowing thesurface of the expandable member 505 to slide smoothly relative toprotrusions that can exist within the bone structure. The use of alubricious outer sheath 543 can also eliminate the need for a lubriciouscoating, which can be difficult to apply and can, at times, becomeineffective. In some embodiments, the outer sheath can be constructedfrom a fluoropolymer, such as for example, polytetrafluoroethylene(i.e., Teflon). Similarly, the outer sheath 543 can be constructed usingany suitable manufacturing process, such as, for example, an extrusionprocess.

As shown in FIG. 46, the outer sheath 543 includes a tapered distal end545 covering both the distal bond portion 538 of the inner layer 542 andthe distal end portion 507 of the stylet 504. This arrangement can allowfor easier insertion.

The outer sheath 543 is coupled to the inner layer 542 by a pair ofclamps 544 disposed on the distal bond portion 538 and the proximal bondportion 539 of the expandable member 505. The clamps 544 can be, forexample, elastic bands, inelastic tie-wrap type clamps, spring clamps,swaged clamps or the like. The clamps 544 can be constructed from anysuitable material, such as for example, stainless steel or nitinol.Moreover, in some embodiments, the clamps 544 can include a radio-opaquematerial, such as titanium or platinum.

In some embodiments, the clamps 544 also couple the expandable member505 to the stylet 504 and the outer shaft 503 of the catheter. In suchan embodiment, the clamps 544 are configured to provide sufficientclamping force to maintain a fluid-tight seal at the distal bond portion538 and the proximal bond portion 539. In other embodiments, asdiscussed in more detail herein, the expandable member 505 is coupled tothe stylet 504 and the outer shaft 503 independently from the clamps544.

In some embodiments, the outer sheath 543 can be coupled to the innerlayer 542 before any pleats, folds or the like are formed in the innerlayer 542. In this manner, the pleats and/or folds are formed in theinner layer 542 and the outer sheath 543 simultaneously. In otherembodiments, the outer sheath 543 can be coupled to the inner layer 542after inner layer 542 has been pleated. In this manner, any folds and/orpleats formed the outer sheath 543 can be configured differently fromthose formed in the inner layer 542. In yet other embodiments, the outersheath 543 can be devoid of any folds and/or pleats, relying insteadupon other properties, such as for example high elasticity, to maintaina low profile when in the collapsed configuration.

Although the outer surface of the inner layer 542 is shown in FIG. 46 asbeing in continuous contact with the inner surface of the outer sheath543 when the expandable member 505 is in the expanded configuration, insome embodiments, the outer surface of the inner layer 542 and the innersurface of the outer sheath 543 may not be in continuous contact whenthe expandable member 505 is in the collapsed and/or expandedconfiguration. For example, in some embodiments, because clamps 544 areused to couple the outer sheath 543 to the inner layer 542, the innerlayer 542 may not be in continuous contact with the inner surface of theouter sheath 543. In this manner, for example, the inner layer 542 canmove relative to the outer sheath 543 when the inner layer 542 and theouter sheath 543 are collectively moved between the collapsedconfiguration and the expanded configuration.

For example, FIG. 47 shows an example of an expandable member 505′according to an embodiment of the invention in a collapsedconfiguration. As described above, the expandable member 505′ includesan inner layer 542′ and an outer sheath 543′ disposed about the innerlayer 542′. The inner layer 542′ has multiple pleats 540′. As shown inFIG. 47, the pleats 540′ are folded circumferentially to minimize theprofile (e.g., the outer diameter) of the expandable member 505′ when inits collapsed configuration. As shown in FIG. 47, the outer sheath 543′is disposed about the inner layer 542′ such that the outer sheath 543′is not in continuous contact with an inner layer 542′.

Although the outer sheath 543 and the inner layer 542 are shown anddescribed as being coupled by a pair of clamps 544, in some embodiments,the outer sheath 543 can be coupled to the inner layer 542 by anysuitable means. For example, in some embodiments, the outer sheath 543can be coupled to the inner layer 542 via an adhesive, a thermal bond,an ultraviolet radiation (UV) bond or the like. In other embodiments,the outer sheath 543 is constructed from a material having a sufficientelasticity and size to remain coupled to the inner layer 542 without theneed for an adhesive, clamp or the like.

Although the outer sheath 543 is shown and described as coveringsubstantially the entire inner layer 542, in some embodiments, the outersheath 543 can cover only a portion of the inner layer 542. FIG. 48shows an example of an expandable member 605 that includes an outersheath 643 that covers only a portion of an inner layer 642. Similar tothe expandable members described above, the expandable member 605includes a distal tapered portion 636, a proximal tapered portion 635and a central portion 634 disposed between the distal tapered portion636 and the proximal tapered portion 635. The proximal tapered portion635 terminates in a proximal bond portion 639 and the distal taperedportion 636 terminates in a distal bond portion 638.

The expandable member 605 has an inner layer 642 constructed from afirst material and an outer sheath 643 constructed from a secondmaterial, different than the first material. The outer sheath 643 iscoupled to and disposed about the central portion 634 of the inner layer642. In this manner, central portion 634, which can, in someembodiments, be thinner than the distal tapered portion 636 and theproximal tapered portion 635, can be selectively reinforced. Moreover,in some embodiments, when the expandable member 605 is in its expandedconfiguration, the central portion 634 can be the portion of theexpandable member 605 configured to contact and/or displace bone thatcan be abrasive, sharp and/or cause punctures. Accordingly, constructingthe expandable member such that the outer sheath 643 is disposed about acentral portion of the expandable member, the expandable member 605 canbe configured to resist such damage.

Although the outer sheath 643 is shown and described as covering thecentral portion 634 of the inner layer 642, in other embodiments, theouter sheath 643 can be configured to cover a different portion of theinner layer 642. For example, in some embodiments, an expandable membercan be deployed in a bone structure such that the distal tapered portionis the portion of the expandable member that is configured to contactand/or displace bone. In such an embodiment, the distal tapered portioncan be selectively reinforced. Moreover, the outer sheath 643 need notbe disposed symmetrically about the inner layer 642.

Although the expandable members shown and described above include twolayers, in some embodiments, an expandable member can include anysuitable number of layers. For example, in some embodiments, anexpandable member can include an inner layer, an intermediate layerdisposed substantially about the entire inner layer and an outer layerdisposed selectively about less than the entirety of the intermediatelayer.

In some embodiments, an expandable member can include a coating appliedto the exterior surface of the expandable member to improve thelubricity, abrasion resistance, tear resistance and/or punctureresistance of the expandable member. Additionally, a coating can beapplied to enhance the optical properties, such as, for example, theradio-opacity, of the expandable member. In some embodiments, forexample, the coating can be selectively disposed on less than theentirety of the exterior surface. For example, in some embodiments, anabrasion resistant coating can be applied to those portions of theexterior surface configured to contact bone.

The coating can include any material suitable for being applied to apolymeric substrate and having suitable properties, such as, forexample, biocompatibility, abrasion resistance, hardness, tearresistance, puncture resistance, lubricity and the like. In someembodiments, for example, the coating can be an aliphatic elastomer,such as polyurethane, silicone, polyether block amide (PEBAX®),polyvinyl chloride (PVC) or the like. In other embodiments, the coatingcan be a hydrogel configured to improve the lubricity of the expandablemember. In yet other embodiments, the coating can include an inorganicfiller to provide increased durability. For example, in someembodiments, the coating can include a ceramic material, such astitanium carbide, disposed within a polymeric matrix.

Although described as including a single coating, in some embodiments,an expandable member can include multiple coatings. For example, in someembodiments an expandable member can include an abrasion resistantcoating disposed on substantially the entire exterior surface and alubricious coating disposed on the proximal portion of the exteriorsurface. The location of such a lubricious coating can be selected, forexample, to improve the ease with which the expandable member can beinserted and/or removed from a cannula and/or a bone structure within abody. In other embodiments, an expandable member can include an abrasionresistant coating disposed on substantially the entire exterior surfaceand a therapeutic coating disposed on a portion of the exteriorsurfaces. Such therapeutic coatings can include, for example, a coatingconfigured to sterilize the bone structure In yet other embodiments, anexpandable member can include one or more layers of an abrasionresistant coating and one or more layers of a hydrophilic coating.

In alternative embodiments, an expandable member can include areinforcement member to reinforce portions of the expandable member. Forexample, FIG. 49 is a perspective view of an expandable member 705according to an embodiment of the invention that includes areinforcement member 746. As described above, the expandable member 705includes a distal tapered portion 736, a proximal tapered portion 735and a central portion 734 disposed between the distal tapered portion736 and the proximal tapered portion 735. The proximal tapered portion735 terminates in a proximal bond portion 739 and the distal taperedportion 736 terminates in a distal bond portion 738. The reinforcementmember 746 is disposed along an outer surface 747 of the central portion734 expandable member 705. As illustrated, the reinforcement member 746can be arranged spirally about the longitudinal axis La of theexpandable member 705. In some embodiments, the reinforcement member 746can be a single member that is wound around the central portion 734 ofthe expandable member 705 a predetermined number of turns. In otherembodiments, the expandable member 705 can include multiplereinforcement members 746 arranged substantially parallel to each otherand disposed radially about the circumference of the central portion 734of the expandable member 705. The reinforcement member 746 can beconstructed of any material having suitable properties, such asflexibility, elasticity, tensile strength and/or biocompatibility.Examples of materials from which the reinforcement member 746 can beconstructed include Vectran, Kevlar, Nylon and the like.

The reinforcement member 746 can reinforce portions of the wall 742 ofthe expandable member 705, without significantly increasing the profileof the expandable member 705. For example, in some embodiments, theinclusion of a reinforcement member 746 can increase the rated burstpressure of the expandable member 705. In other embodiments, forexample, in those embodiments in which the expandable member 705 has ahigh-compliant wall, the reinforcement member 746 can also preventoverexpansion of the wall 742 during use.

The reinforcement member 746 can have any suitable size and/orcross-sectional shape. In some embodiments, for example, thereinforcement member 746 can be a fiber having a substantially circularcross-sectional having a diameter of 0.25 mm (0.001 in.) or less. Inother embodiments, the reinforcement member 746 can have a substantiallyrectangular cross-section. Similarly, the “wrap density” of thereinforcement member 746 (i.e., the number of reinforcement members perunit length) can be any suitable amount. For example, in someembodiments, the reinforcement member 746 can be disposed about the wallat a wrap density of between 1 and 4 wraps per millimeter. In otherembodiments, the reinforcement member can be disposed about the wall ata wrap density of less than 1 wrap per millimeter or greater than 4wraps per millimeter. In yet other embodiments, the wrap density of thereinforcement member 746 can vary along the longitudinal axis La of theexpandable member. In this manner, the reinforcement member 746 can beconcentrated in areas of the expandable member 705 where greaterreinforcement is desired.

FIG. 50 is a perspective view of an expandable member 805 according toan embodiment of the invention that includes a series of reinforcementmembers 846 disposed longitudinally along the expandable member 805. Theexpandable member 805 includes a distal tapered portion 836, a proximaltapered portion 835 and a central portion 834 disposed between thedistal tapered portion 836 and the proximal tapered portion 835. Theproximal tapered portion 835 terminates in a proximal bond portion 839and the distal tapered portion 836 terminates in a distal bond portion838. The reinforcement members 846 are disposed longitudinally along anouter surface 847 of the expandable member 805.

Although the expandable members 705 and 805 are shown and described asincluding a reinforcement member or series of reinforcement membersdisposed either spirally or longitudinally, in other embodiments, anexpandable member can include a first series of reinforcement membersdisposed radially about the circumference of the expandable member and asecond series of reinforcement members disposed longitudinally along thesurface of the expandable member. In other embodiments, a reinforcementmember can be a closely knitted series of fibers (which can be referredto as a “sock”) extending spirally, longitudinally and/or about thecircumference of the expandable member.

Although the expandable members 705 and 805 are shown and described asincluding a reinforcement member or series of reinforcement membersdisposed along the outer surface of the expandable member, in someembodiments, an expandable member can include a reinforcement memberdisposed within the side wall of the expandable member. In otherembodiments, an expandable member can include an inner layer, an outersheath disposed about the inner layer and a reinforcing reinforcementmember disposed between the inner layer and the outer sheath. In yetother embodiments, an expandable member can include a reinforcingreinforcement member disposed on the interior surface of the expandablemember.

FIG. 51 is a flow chart illustrating a method 900 for manufacturing acatheter assembly having an expandable member according to an embodimentof the invention. The illustrated method includes manufacturing theexpandable member, at 910. The expandable members shown and describedabove can be manufactured by a variety of processes, including, forexample, an extrusion process and/or a blow molding process. Examples ofsuch processes are described in U.S. Pat. No. 6,979,341, which isincorporated herein by reference in its entirety. In some embodiments,an expandable member is formed by first extruding a tube and thenshaping the tube using a blow molding process to define the final shapeof the expandable member. During the extrusion process, a variety ofprocess parameters can have an effect on the mechanical properties ofexpandable member. Such process parameters can include, for example, thetemperature profile from the feeding zone of the screw to the tooling,the tooling geometry of the cross head, the screw and/or the barrel, therate at which the tubing is extruded (e.g., the rotation speed of theextrusion gear), the temperature of the cooling bath and/or the distancebetween the tooling and the cooling bath. In some embodiments, forexample, the rate at which the extruded tubing is cooled (i.e., thequench rate) can impact the molecular structure of the tubing. Forexample, in some embodiments, a faster rate of cooling can result in atubing having a more amorphous molecular structure. As discussed above,the level of crystallinity of the molecular structure can impact thecompliance of the expandable member.

Similarly, during the blow molding process, a variety of parameters alsocan influence the properties of the expandable member. Such parameterscan include, for example, the temperature of the heating jaws, thepre-pressure/warm-up time, the forming pressure, the rate of cooling,the annealing time, the stretch rate and/or the stretch distance. Insome embodiments, for example, the forming pressure can impact the burstpressure of the expandable member. For example, in some embodiments,increasing the forming pressure from 1.4 MPa to 2.1 MPa (200 psi to 300psi) can increase the rated burst pressure by approximately 207 KPa (30psi).

Upon completion of the extrusion and/or blow molding processes, themethod includes coupling the expandable member to the catheter assembly,at 920. In particular, referring to FIGS. 39 and 40, the distal bondportion 338 is coupled to the distal end portion 307 of the stylet 304to form a fluid-tight seal. Similarly, the proximal bond portion 339 iscoupled to the outer shaft 303 to form a fluid-tight seal. Moreover, theseal between the expandable member 305 and the catheter assembly 302 isconfigured to withstand the high operating pressures and/or torsionalstress that can be required when using the expandable member 305 todisplace and/or compact bone. For example, in some embodiments, the sealbetween the expandable member and the catheter assembly is configured towithstand inflation pressures of between 1.4 MPa and 2.8 MPa (200 psiand 400 psi). Similarly, in some embodiments, coupling between theexpandable member and the catheter assembly is configured maintain afluid-tight seal when at least a portion of the expandable member istwisted about catheter assembly through at least four revolutions.

The expandable member can be coupled to the catheter assembly using anysuitable technique, such as, for example via an adhesive, a chemicalbond, a UV bond, a laser bond, a shrink fit, a mechanical clamp or thelike. In some embodiments, for example, the expandable member can becoupled to the catheter assembly using clamps similar to the clamps 544shown and described above (see FIG. 30). In other embodiments, theexpandable member can be coupled to the catheter assembly using acombination of techniques. For example, in some embodiments, the distalbond portion can be coupled to the stylet via a UV bond and the proximalbond portion can be coupled to the outer shaft via an adhesive.

In some embodiments, the expandable member can be bonded to the catheterassembly using a radio frequency induction heating process (i.e., an RFbonding process). The RF bonding process is particularly well suited forthose embodiments that include a metallic outer shaft and/or stylet. Forexample, in some embodiments, the distal bond portion of the expandablemember can be bonded to the distal end portion of a stainless steelstylet. First, the distal bond portion of the expandable member isplaced in contact with the stylet. An induction coil is placed around aportion of the stylet and is energized with alternating current at apredetermined power and frequency. The alternating current producesmagnetic field around the stylet, which generates an electrical currentwithin the stylet. The electrical current produce areas of localizedheat, which liquefy the adjacent portions of the expandable member. Theliquid portions then move into the crevices on the surface of thestylet. When the current is removed, the liquid portions of theexpandable member solidify to form a bond. In some embodiments, thesurface of the stylet can be configured to improve the bond between theexpandable member and the stylet. For example, in some embodiments, thesurface of the stylet can be bead blasted to improve the bond betweenthe expandable member and the stylet.

In some embodiments, as described above, a catheter assembly can includea polymeric inner shaft disposed between the stylet and the distal bondportion of the expandable member. The addition of the inner shaft canprovide additional material to form the distal bond, thereby increasingthe strength of the distal bond.

Because RF bonding produces areas of localized heating, a bond can beproduced in the distal bond portion and/or the proximal bond portion ofthe expandable member without subjecting other portions of theexpandable member to heat. In this manner, the expandable member can becoupled to the catheter assembly without further annealing theexpandable member.

In some embodiments, the operation 920 of coupling the expandable memberto the catheter assembly can include multiple different processes, asshown in FIG. 52. First a portion of the stylet is bonded within theinner shaft, 922, as shown and described above with reference to FIGS.40 and 41. In some embodiments, for example, the stylet can be disposedwithin a lumen defined by the inner shaft and bonded over a portion ofthe longitudinal length of the stylet. In other embodiments, the styletcan be bonded within the inner shaft along the entire length of theinner shaft to form a composite member. As described above, in someembodiments, the stylet and the inner shaft can be coupled using an RFbonding process.

The proximal end portion of the expandable member is then coupled to thedistal end portion of the outer shaft, 923. As shown and describedabove, with reference to FIGS. 40 and 41, the axial length of theproximal bond can be, for example, between 1 mm and 7 mm (0.040 in. and0.275 in.). Any suitable method of coupling can be used (e.g., adhesive,a chemical bond, a UV bond, a laser bond, a shrink fit, a mechanicalclamp or the like).

The stylet and inner shaft assembly is then disposed within the lumen ofthe outer shaft, 924. A sleeve, of the type shown and described abovewith reference to FIG. 42 is then disposed about the distal end portionof the inner shaft, 925. As described above, the sleeve can improve thecharacteristics of the distal bond. In some embodiments, the sleeve caninclude a colorant to be excited by a laser used to couple theexpandable member, the inner shaft and the sleeve, as described below.

The distal end portion of the expandable member is then coupled to thedistal end portion of the inner shaft/stylet assembly, 926. In someembodiments, the distal end portion expandable member, the inner shaftand the sleeve can be collectively coupled by using two distinctoperations. First, a thermal bonding process (i.e., the application ofheat to the areas to be bonded) can be used to form a fluid-tight sealat the distal bond location. Second, a laser bond process, whichproduces a more localized heating of the materials, can be used to forma distal bond such that the distal bond can withstand the torsionalstresses, as discussed herein. In this manner, the axial length of thedistal bond can be shortened without sacrificing the strength of thedistal bond.

Although not necessary for the successful manufacture of the catheterassembly, the illustrated method includes applying a coating of the typedescribed above, at 930. The coating can be applied by first placing theexpandable member in its expanded configuration. The outer surface ofthe expandable member is then modified to produce a rough surface and/orotherwise prepare the outer surface for receiving the coating. Suchmodification can be referred to as “priming” or “etching,” and can bedone using any suitable technique. In some embodiments, for example, thesurface of the expandable member is prepared by a plasma-etchingprocess, in which the surface is exposed to a plasma to producemicroscopic grooves for receiving the coating. In other embodiments, theexpandable member is exposed to a thermoplastic polymer, such as forexample parylene (C, D or N) to prepare the outer surface for receivingthe coating.

After the outer surface is sufficiently prepared, the coating is appliedusing a dip coating process. The expandable member is then annealed at atemperature of approximately 60° C. for approximately 2-3 hours tostabilize the coating and/or promote cross-linking between the coatingand the outer surface of the expandable member. Said another way, theannealing operation is done to help ensure that the coating will notcrack, delaminate or otherwise deteriorate when the expandable member isin use.

Although described as being applied in a single layer, in someembodiments, the coating can be applied in multiple layers. For example,in some embodiments, an expandable member can include a single layercoating having a thickness of approximately 5 μm (0.0002 in.). In otherembodiments, an expandable member can include up to six layers of thecoating, having a total thickness of between 20 and 40 μm (0.0008 and0.0016 in.). In yet other embodiments, an expandable member can includemultiple layers of different coatings.

Although the illustrated method includes applying a coating to theexpandable member, in other embodiments a coating need not be applied.For example, in some embodiments, an outer sheath of the type shown anddescribed above can be coupled to the expandable member.

The illustrated method then includes forming the pleats and/or folds ofthe type described above, at 940. The pleats can be formed by placing aportion of the expandable member within a die having an aperture thatincludes the desired form (i.e., the shape and/or size) of the pleats.The die is then moved to compress the expandable member for apredetermined amount of time to form the pleats. In some embodiments, avacuum is applied to the expandable member when the die is compressedabout the expandable member. In other embodiments, the die can be placedabout the expandable member when the expandable member is at leastpartially expanded. In such embodiments, the movement of the die cancause the expandable member to be collapsed. In some embodiments, thedie can include a heating element to heat the expandable member duringthe pleat-forming process. In this manner, the pleats can be “heat set”to induce the pleats to remain after the die is removed.

During the pleat-forming process, a variety of process parameters canhave an effect on the mechanical properties of the expandable member.Such process parameters can include, for example, the amount of timeduring which the expandable member is compressed, the temperature of theexpandable member and/or the pressure of compression. For example, insome embodiments, the temperature at which the expandable member isexposed can be a trade-off between improving the “shape memory” of thepleats and thermally degrading the mechanical characteristics of theexpandable member. Said another way, exposing the expandable member to ahigh temperature can result in improved “shape memory” of the pleats,but can also thermally degrade the mechanical characteristics of theexpandable member. Accordingly, because the expandable members areexposed to high inflation pressures and the harsh environment that canexist within bone structures, in some embodiments, the pleat-formingprocess is configured to avoid compromising the overall characteristicsof the expandable member. In some embodiments, the pleats are formed atapproximately 70° C. under a pressure of no greater than 68 N for aduration of approximately 5 seconds.

The expandable member is then removed from the die and wrapped about theouter shaft and/or stylet to reduce the profile of the expandable memberat 950. In some embodiments, the expandable member is wrapped and/orfolded using the twisting apparatus as shown and described above. Inother embodiments, the expandable member is wrapped and/or folded usinga second die (i.e., a “wrapping die”) that is configured to secure thepleats and rotate relative to the outer shaft of the catheter assembly.In some embodiments, the expandable member is folded at an elevatedtemperature and/or pressure. For example, in some embodiments, anexpandable member can be folded at approximately 80° C. under a pressureof no greater than 133 N for a duration of approximately 150 seconds. Aprotective sleeve (not shown in the above figures) is then disposedabout the expandable member. In some embodiments, the assembly (e.g.,the expandable member and the protective sleeve) is annealed to furtherimprove the “shape memory” of the expandable member.

The protective sleeve can be, for example, an extruded polymeric sleeveconstructed of a PEBAX® blend. In some embodiments, for example, theprotective sleeve can include a colorant. In this manner, the protectivesleeve can serve to identify certain characteristics of the expandablemember and/or the catheter assembly. For example, in some embodimentsthe size of the expandable member can be correlated to the color of theprotective sleeve.

The illustrated method then includes disposing an outer sheath of thetype shown and described above over the expandable member, at 960. Asdescribed above, the outer sheath can be secured to the expandablemember by an adhesive, a clamp or the like.

FIG. 53 is a flow chart illustrating a method 970 according to anembodiment of the invention. The illustrated method includes moving anactuator from a first position to a second position such that a firstshaft is rotatable relative to a second shaft, 971. The second shaft isdisposed within the first shaft and is coupled to an expandable member.The actuator is then moved from the second position to the firstposition such that the second shaft is rotatable relative to the firstshaft through a plurality of discrete increments, 972. In someembodiments, for example, the first shaft and the second shaft can be aportion of a catheter assembly that includes an actuator, as describedabove.

In some embodiments, the method 970 can optionally includepercutaneously inserting into a body at least a distal portion of thefirst shaft and at least a distal portion of the second shaft before themoving the actuator from the first position to the second position andbefore the moving the actuator from the second position to the firstposition. In this manner, for example, the expandable member can bedisposed within a bone structure.

In other embodiments, the method can optionally include moving theexpandable member from a first collapsed configuration to an expandedconfiguration after the moving the actuator from the first position tothe second position. In this manner, as described above, the expandablemember can displace a portion of a bone structure. In yet otherembodiments, the method can include moving the expandable member fromthe expanded configuration to a second collapsed configuration after themoving the expandable member from the first collapsed configuration.

In other embodiments, the method can optionally include removing fromthe body the distal portion of the first shaft and the distal portion ofthe second shaft after the moving the actuator from the first positionto the second position and after the moving the actuator from the secondposition to the first position.

FIG. 54 is a flow chart illustrating a method 975 according to anembodiment of the invention. The illustrated method includes engaging aratchet of a first member with a pawl portion of a second member, 976.The first member is coupled to a first shaft, as described above. Thesecond member is coupled to a second shaft such that the second shaftcan rotate relative to the first shaft in a first direction. The secondshaft coupled to an expandable member. In this manner, rotation of thesecond shaft relative to the first shaft can twist at least a portion ofthe expandable member about the second shaft, as described above. Theratchet of the first member is disengaged from the pawl portion of thesecond member such that that the second shaft can rotate relative to thefirst shaft in a second direction opposite the first direction, 977.

FIG. 55 is a flow chart illustrating a method 980 according to anembodiment of the invention. The illustrated method includes insertinginto a body a catheter assembly, 981. The catheter assembly, which canbe any suitable catheter assembly as shown and described above, includesa shaft and an expandable member coupled to the shaft. In someembodiments, the inserting includes disposing the expandable memberwithin a bone structure. In some embodiments, the catheter assembly isinserted via a cannula.

The expandable member is moved from a first collapsed configuration toan expanded configuration, 982. In some embodiments, at least a portionof a bone structure is displaced relative to another portion of the bonestructure when the expandable member is moved from its first collapsedconfiguration to its expanded configuration.

The expandable member is moved from the expanded configuration to asecond collapsed configuration, 983, after the moving the expandablemember from the first collapsed configuration. In some embodiments, thesecond collapsed configuration can be different than the first collapsedconfiguration. In other embodiments, the second collapsed configurationcan be substantially the same as the first collapsed configuration.

The expandable member is then rotated about a centerline of the shaftthrough a plurality of discrete increments, 984. In this manner, asdescribed above, the profile of the expandable member can be reduced. Insome embodiments, the method can optionally include removing thecatheter assembly from the body after the expandable member has beenrotated, 985.

FIG. 56 is a flow chart illustrating a method 990 according to anembodiment of the invention. The illustrated method includes insertinginto a body a distal portion of a catheter assembly, 991. The catheterassembly includes a shaft and an expandable member coupled to the shaft.In some embodiments, the catheter assembly is inserted via a cannula.

The expandable member is then moved from a first collapsed configurationto an expanded configuration, 992. In some embodiments, an end plate ofthe vertebral body is displaced when the expandable member is moved fromits first collapsed configuration to its expanded configuration.

The expandable member then is moved from the expanded configuration to asecond collapsed configuration, 993, after the moving the expandablemember from the first collapsed configuration. In some embodiments, thesecond collapsed configuration can be different than the first collapsedconfiguration. In other embodiments, the second collapsed configurationcan be substantially the same as the first collapsed configuration.

A knob coupled to a proximal portion of the catheter assembly is thenrotated in a first direction such that the expandable member is twistedabout a centerline of the shaft, 994. The knob, which can be any knob ofthe type shown and described above, is configured to resist rotation ina second direction opposite the first direction. In this manner, theprofile of the expandable member can be reduced. The distal portion ofthe catheter assembly is then from the vertebral body, 995.

FIG. 57 is a flow chart illustrating a method 1900 according to anembodiment of the invention. The illustrated method includes insertinginto a body a catheter assembly, 1902. The catheter assembly, which canbe any catheter assembly as shown and described above, includes anexpandable member, a shaft having a distal end portion coupled to aproximal end portion of the expandable member, and an elongated memberrotatably disposed within the shaft. A distal end portion of theelongated member is coupled to a distal end portion of the expandablemember. In this manner, when the elongated member is rotated relative tothe shaft, at least a portion of the expandable member is twisted aboutthe elongated member. In some embodiments, the inserting includesdisposing the expandable member within a bone structure. In someembodiments, the catheter assembly is inserted via a cannula.

The expandable member is moved from a collapsed configuration to anexpanded configuration, 1904. In some embodiments, a bone structure isdisplaced when the expandable member is moved from its first collapsedconfiguration to its expanded configuration. The expandable member isthen moved from the expanded to the collapsed configuration, 1906.

At least a portion of the elongate member is then rotated relative tothe shaft such that at least a portion of the expandable member istwisted about the elongated member through at least four revolutionswhile maintaining a fluid-tight seal between the distal end portion ofthe expandable member and the distal end portion of the elongatedmember, 1908. In this manner, as described above, the profile (e.g., thediameter) of the expandable member when in the collapsed configurationcan be reduced such that it less than a diameter of a cannula. In someembodiments, the method optionally includes removing the expandablemember from the body via the cannula, 1910.

FIG. 58 is a flow chart illustrating a method 1920 according to anembodiment of the invention. The illustrated method includes insertingan expandable member into an interior portion of a bone structure, 1922.As described above with reference to FIG. 47, the expandable memberincludes a first layer and a second layer. The second layer is disposedabout the first layer such that an outer surface of the first layer isin discontinuous contact with an inner surface of the second layer. Thefirst layer constructed from a first polymer having a molecularstructure. The second layer constructed from a second polymer having amolecular structure more amorphous than the molecular structure of thefirst polymer.

In some embodiments, the expandable member is inserted via a cannula. Insome embodiments, the bone structure can be a vertebral body. In someembodiments, the bone structure can include recalcitrant bone, such asthe type of recalcitrant bone found in bone defects that are more thanthree months old.

The expandable member is then expanded while disposed within theinterior portion of the bone structure such that the expandable memberexerts a force sufficient to cause a first portion of the bone structureto move relative to a second portion of the bone structure, 1924. Insome embodiments, the expanding includes inflating the expandable memberto a pressure of at least 1.4 Megapascals. In other embodiments, theexpanding includes inflating the expandable member to a pressure of atleast 2.8 Megapascals. In yet other embodiments, the expanding includesinflating the expandable member to a pressure of at least 5.5Megapascals.

In some embodiments, the first layer of the expandable member is movedrelative to the second layer of the expandable member when theexpandable member is expanded.

While various embodiments of the invention have been described above, itshould be understood that they have been presented by way of exampleonly, and not limitation. Where methods described above indicate certainevents occurring in certain order, the ordering of certain events may bemodified. Additionally, certain of the events may be performedconcurrently in a parallel process when possible, as well as performedsequentially as described above. Thus, the breadth and scope of theinvention should not be limited by any of the above-describedembodiments. While the invention has been particularly shown anddescribed with reference to specific embodiments thereof, it will beunderstood that various changes in form and details may be made.Finally, all publications and patent applications cited in thisspecification are herein incorporated by reference in their entirety asif each individual publication or patent application were specificallyand individually put forth herein.

For example, although the twisting apparatuses described herein areshown and described as being used to rotate an expandable memberrelative to a catheter, in other embodiments, a twisting apparatus canbe used to control the twisting of other medical devices. For example,in some embodiments, a twisting apparatus according to an embodiment ofthe invention can be used to rotate a portion of a spinal implant and/orimplant insertion tool. In other embodiments, a twisting apparatusaccording to an embodiment of the invention can be used to rotate aportion of a bone screw and/or bone screw insertion device.

Although the twisting apparatuses described herein include a secondmember configured to rotate relative to a first member therebycontrolling the rotation of an elongated member, in other embodiments, atwisting apparatus can include a second member configured to movelinearly relative to a first member to control the rotation of anelongated member. For example, in some embodiments, a second member caninclude a trigger style actuator configured to rotate the elongatedmember in discrete amounts.

Although the twisting apparatuses described herein include a secondmember configured to rotate about a longitudinal axis of a stylet, inother embodiments, the second member can be configured to rotate aboutan axis that is offset from the longitudinal axis of the stylet. In yetother embodiments, the second member can be configured to rotate aboutan axis that is angularly offset from the longitudinal axis of thestylet.

Although the twisting apparatuses described herein include a secondmember engaged with an elongated member such that rotation of the secondmember causes equal rotation of the elongated member, in otherembodiments, the elongated member can be configured to rotate with thesecond member at a ratio other than 1:1. For example, in someembodiments, a twisting apparatus includes a gear reducer disposedbetween the second member and the elongated member. In this manner,rotation of the second member over a set angular distance can result inrotation of the elongated member over a different angular distance. Inother embodiments, a gear reducer can be configured to change thedirection of rotation of the elongated member with respect to the secondmember.

For example, although the method 900 includes coupling an outer sheathto the expandable member after the pleat-forming process is completed,in other embodiments, the outer sheath can be coupled to the expandablemember before the pleats are formed in the expandable member. In thismanner, the expandable member and the outer sheath can includecomplimentary pleats. In yet other embodiments, an outer sheath is notcoupled to the expandable member. Similarly, in some embodiments, acoating need not be applied to the expandable member.

Although the expandable members shown and described include an outersheath or a coating, in some embodiments, an expandable member caninclude an outer sheath and a coating disposed on the outer sheath. Forexample, in some embodiments, an expandable member can include an outersheath configured increase the tear resistance of the expandable memberand a coating configured to sterilize a portion of the body.

Although the catheter assemblies are shown and described as including anouter shaft and a stylet, in some embodiments a catheter assembly caninclude an outer shaft, an inner shaft disposed within the outer shaftand a stylet disposed within the inner shaft. In such an arrangement,the inner shaft can extend along with the stylet to the distal bondportion of the expandable member.

Although various embodiments have been described as having particularfeatures and/or combinations of components, other embodiments arepossible having a combination of any features and/or components from anyof embodiments as discussed above. For example, one such embodimentincludes a catheter assembly, an expandable member and a twistingapparatus, as described further below.

The catheter assembly includes an outer shaft, an inner shaft, a styletand a Y-connector. The outer shaft is extruded using a blend of Nylon12, nano-composite fillers and colorant. The wall of the outer shaftdefines an inflation lumen and provides rigidity and sufficient columnstrength to withstand internal pressure from inflation, to preventbuckling during insertion and/or to provide torque resistance during useof the twisting device, as described above. The inner shaft is extrudedusing Nylon 12 and defines a lumen for receiving the stylet. A portionof the inner shaft includes a bonding surface for bonding the innershaft to the stylet, as described above. The stylet is disposed withinthe inner shaft and transmits torque from the twisting apparatus to thedistal end portion of the expandable member. The stylet is constructedfrom stainless steel and includes a “U” shaped proximal end portion tobe received within the twisting apparatus, as described above. Thedistal end portion of the stylet is bead-blasted to provide an outersurface to be bonded to the inner shaft.

The Y-connector is molded with a blend of polycarbonate and includes acolorant. The Y-connector is an interface for the outer shaft, innershaft/stylet sub-assembly, the twisting apparatus and the source ofinflation fluid. The Y-connector includes a “one-way” fluid valve tocontrol the flow of the inflation fluid to the inflation lumen describedabove.

The expandable member is constructed from a polyamide (PA), using a hotmold balloon blowing technology, as described above. The externalsurface of the expandable member includes an aliphatic polyester (poly)urethane coating to improve the abrasion and durability of theexpandable member. During manufacture, the expandable member is coatedby first priming the outer surface thereof with an acrylic copolymer andthen applying the coating on the outer surface. The coating is thencross linked and cured by one or more annealing operations, as describedabove. In some embodiments, the coating can include an inorganic fillerfor increased durability.

As described above, the expandable member is a low-compliant expandablemember having a geometry. More particularly, the expandable member isapproximately ten percent compliant and has a burst pressure ofapproximately 350 psi. Moreover, the expandable member is resistant tochemical corrosion and/or degradation, exerts a higher dynamic force andhas an puncture and/or abrasion resistance of approximately 12 lbf usingthe test shown and described above.

An protective insertion sleeve is disposed about the expandable memberto protect the expandable member and/or retain the desired shape of theexpandable member prior to use. The protective insertion sleeve can beconstructed from PEBAX® and a colorant.

The twisting apparatus is configured to twist the expandable member byapplying a rotational force to the distal end portion of the expandablemember, as described above. The twisting apparatus also includes aratchet mechanism to prevent the loss of torsional force during thetwisting operation. The components included in the twisting apparatusare constructed from Nylon and ABS and are assembled using acyanoacrylate adhesive. As described above, the twisting apparatus iscoupled to the luer cap portion of the catheter assembly. The luer capis constructed from polycarbonate and includes a coupling portion forcoupling the inner shaft/stylet assembly to the outer shaft.

1. An apparatus, comprising: a support member coupled to a shaft of acatheter assembly; and a knob configured to engage a stylet of thecatheter assembly, the knob configured to rotate relative to the supportmember through a plurality of discrete increments when an engagementportion of the knob is engaged with an engagement portion of the supportmember.
 2. The apparatus of claim 1, wherein the catheter assemblyincludes an expandable member coupled to the shaft and the stylet suchthat when the knob is rotated relative to the support member, at least aportion of the expandable member is twisted about a longitudinal axis ofthe catheter assembly.
 3. The apparatus of claim 1, wherein the catheterassembly includes an elongated member disposed about the stylet.
 4. Theapparatus of claim 1, wherein each discrete increment from the pluralityof discrete increments is less than one revolution of the knob.
 5. Theapparatus of claim 1, wherein at least one discrete increment from theplurality of discrete increments is equal to one revolution of the knob.6. The apparatus of claim 1, wherein the knob is configured to rotateunidirectionally relative to the support member when the engagementportion of the knob is engaged with the engagement portion of thesupport member.
 7. The apparatus of claim 1, wherein: the knob isconfigured to rotate unidirectionally relative to the support memberwhen the engagement portion of the knob is engaged with the engagementportion of the support member; and the knob is configured to rotatebidirectionally relative to the support member when the engagementportion of the knob is disengaged from the engagement portion of thesupport member.
 8. The apparatus of claim 1, wherein each discreteincrement from the plurality of discrete increments is associated with aplurality of recesses defined by at least one of the engagement portionof the support member or the engagement portion of the knob.
 9. Theapparatus of claim 1, wherein each discrete increment from the pluralityof discrete increments is associated with a plurality of protrusionsincluded on at least one of the engagement portion of the support memberor the engagement portion of the knob.
 10. The apparatus of claim 1,wherein: the engagement portion of the support member includes aplurality of ratchet teeth; the engagement portion of the knob includesa plurality of pawl teeth configured to complimentarily couple to theplurality of ratchet teeth; and a discrete increment from the pluralityof discrete increments is associated with a ratchet tooth from theplurality of ratchet teeth and a pawl tooth from the plurality of pawlteeth.
 11. The apparatus of claim 1, further comprising a rotationlimiter configured to limit a number of revolutions through which theknob can be rotated relative to the support member.
 12. The apparatus ofclaim 1, further comprising: a first rotation limiter configured tolimit a number of revolutions through which the knob can be rotatedrelative to the support member in a first direction; and a secondrotation limiter configured to limit a number of revolutions throughwhich the knob can be rotated relative to the support member in a seconddirection opposite the first direction.
 13. The apparatus of claim 1,further comprising a rotation indicator configured to indicate a numberof revolutions that the knob has rotated relative to the support member.14. The apparatus of claim 1, wherein the engagement portion of the knoband the engagement portion of the support member are configured tocooperatively produce an audible sound when the knob rotates relative tothe support member through a discrete increment from the plurality ofdiscrete increments and when the engagement portion of the knob isengaged with the engagement portion of the support member.
 15. Theapparatus of claim 1, wherein the engagement portion of the knob and theengagement portion of the support member are configured to cooperativelyproduce a haptic output when the knob rotates relative to the supportmember through a discrete increment from the plurality of discreteincrements and when the engagement portion of the knob is engaged withthe engagement portion of the support member.
 16. The apparatus of claim1, wherein: the knob is disposed about and concentric with the supportmember; and the support member defines a lumen through which the styletis disposed.
 17. The apparatus of claim 1, wherein the knob defines anopening configured to receive a portion of the stylet of the catheterassembly such that the stylet can move longitudinally relative to theknob.
 18. An apparatus, comprising: an elongate assembly having a firstshaft and a second shaft disposed within the first shaft, the firstshaft configured to be coupled to a proximal portion of an expandablemember, the second shaft configured to be coupled to a distal portion ofthe expandable member; and an actuator configured to rotate the secondshaft relative to the first shaft through a plurality of discreteincrements.
 19. The apparatus of claim 18, wherein at least a portion ofthe expandable member is twisted about a centerline of the second shaftwhen the actuator rotates the second shaft relative to the first shaft.20. The apparatus of claim 18, wherein the elongate assembly furtherincludes a stylet disposed within the second shaft.
 21. The apparatus ofclaim 18, wherein: the first shaft includes a first catheter; and thesecond shaft includes a second catheter.
 22. The apparatus of claim 18,wherein each discrete increment from the plurality of discreteincrements is less than one revolution of the second shaft.
 23. Theapparatus of claim 18, wherein each discrete increment from theplurality of discrete increments is approximately thirty degrees ofrotation of the second shaft.
 24. The apparatus of claim 18, wherein theactuator is configured to selectively limit the direction of rotation ofthe second shaft relative to the first shaft.
 25. The apparatus of claim18, wherein: the actuator is configured to rotate the second shaftrelative to the first shaft through the plurality of discrete incrementsin a first direction and to prevent the rotation of the second shaftrelative to the first shaft in a second direction opposite the firstdirection when in a first configuration; and the actuator is configuredto rotate the second shaft relative to the first shaft in the firstdirection and the second direction when in a second configuration. 26.The apparatus of claim 18, wherein the actuator is configured to limit anumber of revolutions through which the second shaft can be rotatedrelative to the first shaft.
 27. The apparatus of claim 18, wherein theactuator is configured to produce an indication associated with anangular displacement of the second shaft relative to the first shaft.28. The apparatus of claim 18, wherein: the actuator includes: a ratchetwheel configured to be coupled to the first shaft of the elongateassembly, the ratchet wheel having a plurality of ratchet teeth; and aknob configured to engage the second shaft of the elongate assembly suchthat when the knob is rotated relative to the ratchet wheel, the secondshaft is rotated relative to the first shaft, the knob including atleast one pawl, each discrete increment from the plurality of discreteincrements is associated with a ratchet tooth from the plurality ofratchet teeth.
 29. The apparatus of claim 18, wherein: the actuatorincludes: a ratchet wheel configured to be coupled to the first shaft ofthe elongate assembly, the ratchet wheel having a plurality of ratchetteeth; and a knob configured to engage the second shaft of the elongateassembly, the knob including at least one pawl configured to engage aportion of each ratchet tooth from the plurality of ratchet teeth and todefine each discrete increment from the plurality of discrete incrementswhen the knob is rotated relative to the ratchet wheel.
 30. Theapparatus of claim 18, wherein: the actuator includes: a ratchet wheelconfigured to be coupled to the first shaft of the elongate assemblysuch that the ratchet wheel can move longitudinally relative to thefirst shaft, the ratchet wheel having a plurality of ratchet teeth; anda knob defining an opening configured to receive a portion of the secondshaft of the elongate assembly such that when the knob is rotatedrelative to the ratchet wheel, the second shaft is rotated relative tothe first shaft and such that the second shaft can move longitudinallyrelative to the knob, each discrete increment from the plurality ofdiscrete increments is associated with a ratchet tooth from theplurality of ratchet teeth.
 31. An apparatus, comprising: a first memberhaving a ratchet wheel, the first member coupled to a catheter; and asecond member having a pawl portion, the second member engaging a shaftrotatably disposed within the catheter, the pawl portion of the secondmember configured to engage the ratchet wheel of the first member tocooperatively resist the rotation of the second member with respect tothe first member when the second member and the first member arecollectively in a first configuration, the pawl portion of the secondmember configured to be spaced apart from the ratchet wheel of the firstmember when the second member and the first member are collectively in asecond configuration.
 32. The apparatus of claim 31, wherein the shaftincludes a stylet.
 33. The apparatus of claim 31, wherein: the catheteris a first catheter; and the shaft is a second catheter.
 34. Theapparatus of claim 31, wherein the pawl portion and the ratchet wheelare configured to cooperatively prevent the rotation of the secondmember with respect to the first member in a second direction oppositethe first direction when the second member and the first member arecollectively in the first configuration.
 35. The apparatus of claim 31,wherein: the ratchet wheel of the first member includes a plurality ofratchet teeth; and the second member is configured to rotate relative tothe first member through a plurality of discrete increments when thesecond member and the first member are collectively in the firstconfiguration, each discrete increment from the plurality of discreteincrements being associated with a ratchet tooth from the plurality ofratchet teeth.
 36. The apparatus of claim 31, wherein: the ratchet wheelof the first member includes a plurality of ratchet teeth; the pawlportion of the second member includes at least one pawl; and the atleast one pawl is configured to engage each ratchet tooth from theplurality of ratchet teeth when the second member and the first memberare collectively in the first configuration and when the second memberis rotated with respect to the first member.
 37. The apparatus of claim31, wherein: the first configuration corresponds to a first longitudinalposition of the second member with respect to the first member; and thesecond configuration corresponds to a second longitudinal position ofthe second member with respect to the first member different from thefirst longitudinal position.
 38. The apparatus of claim 31, furthercomprising a biasing member configured to bias the first member and thesecond member in the first configuration.
 39. The apparatus of claim 31,wherein the second member defines an opening configured to receive aportion of the shaft such that the shaft can move longitudinallyrelative to the catheter.
 40. The apparatus of claim 31, wherein thefirst member is configured to be coupled to the catheter such that thefirst member can move longitudinally relative to the catheter.
 41. Theapparatus of claim 31, further comprising a rotation limiter configuredto limit a number of revolutions through which the second member can berotated relative to the first member.
 42. The apparatus of claim 31,further comprising a rotation indicator configured to indicate a numberof revolutions that the knob has rotated relative to the support member.43. The apparatus of claim 31, wherein an inner surface of the secondmember defines a lumen within which at least a portion of the firstmember is disposed, the apparatus further comprising: a rotationindicator threadedly disposed on an outer surface of the first member,the rotation indicator including a protrusion configured to be receivedwithin a groove defined by the inner surface of the second member suchthat rotation of the second member with respect to the first membercauses the rotation indicator to rotate about the outer surface of thefirst member.
 44. An apparatus, comprising: a support member configuredto be coupled to a shaft of a catheter assembly; and a knob configuredto engage an elongated member of the catheter assembly rotatablydisposed within the shaft of the catheter assembly, the knob configuredto rotate unidirectionally relative to the support member when thesupport member and the knob are collectively in a first configuration,the knob is configured to rotate bidirectionally relative to the supportmember when the support member and the knob are collectively in a secondconfiguration.
 45. The apparatus of claim 44, further comprising thecatheter assembly, including an expandable member coupled to the shaft.46. The apparatus of claim 44, further comprising: the catheter assemblyincluding an expandable member having a proximal end portion coupled toa distal end portion of the shaft and a distal end portion coupled to adistal end portion of the elongated member such that when the knob isrotated relative to the support member, at least a portion of theexpandable member is twisted about a longitudinal axis of the catheterassembly.
 47. The apparatus of claim 44, further comprising theelongated member including a stylet disposed therein.
 48. The apparatusof claim 44, wherein the shaft is a first shaft, the apparatus furthercomprising: the catheter assembly including a second shaft disposed withthe first shaft and about the elongated member.
 49. The apparatus ofclaim 44, wherein: the knob has a pawl portion; and the support memberhas a ratchet wheel, the pawl portion of the knob configured to engagethe ratchet wheel of the support member to cooperatively prevent therotation of the knob with respect to the support member in a seconddirection opposite a first direction when the support member and theknob are collectively in the first configuration, the pawl portion ofthe knob configured to be spaced apart from the ratchet wheel of thesupport member when the support member and the knob are collectively inthe second configuration.
 50. The apparatus of claim 44, wherein theknob is configured to rotate relative to the support member through aplurality of discrete increments when the support member and the knobare collectively in the first configuration.
 51. The apparatus of claim44, wherein the knob is configured to rotate relative to the supportmember through a plurality of discrete increments when the supportmember and the knob are collectively in the first configuration, eachdiscrete increment from the plurality of discrete increments being lessthan one revolution of the knob.
 52. The apparatus of claim 44, wherein:the support member has a ratchet wheel including a plurality of ratchetteeth; the knob has a pawl portion including a plurality of pawl teethconfigured to complimentarily couple to the plurality of ratchet teeth;and the knob is configured to rotate relative to the support memberthrough a plurality of discrete increments when the support member andthe knob are collectively in the first configuration, a discreteincrement from the plurality of discrete increments is associated with aratchet tooth from the plurality of ratchet teeth and a pawl tooth fromthe plurality of pawl teeth.
 53. The apparatus of claim 44, wherein: thefirst configuration corresponds to a first longitudinal position of theknob with respect to the support member; and the second configurationcorresponds to a second longitudinal position of the knob with respectto the support member different from the first longitudinal position.54. The apparatus of claim 44, further comprising a biasing memberconfigured to bias the knob and the support member in the firstconfiguration.
 55. The apparatus of claim 44, further comprising arotation indicator configured to indicate a number of revolutions thatthe knob has rotated relative to the support member.
 56. The apparatusof claim 44, further comprising a rotation limiter configured to limit anumber of revolutions through which the knob can be rotated relative tothe support member.
 57. The apparatus of claim 44, wherein the knobdefines an opening configured to receive a portion of the elongatedmember of the catheter assembly such that the elongated member can movelongitudinally relative to the knob.
 58. The apparatus of claim 44,wherein the support member is configured to be coupled to the shaft ofthe catheter assembly such that the support member can movelongitudinally relative to the shaft.
 59. An apparatus, comprising: acatheter assembly having a first shaft and a second shaft disposedwithin the first shaft; an expandable member having a proximal portioncoupled to the first shaft and a distal portion coupled to the secondshaft; and an actuator configured to rotate the second shaft relative tothe first shaft in a first direction to twist at least a portion of theexpandable member about a centerline of the second shaft, the actuatorconfigured to prevent rotation of the second shaft relative to the firstshaft in a second direction opposite the first direction.
 60. Theapparatus of claim 59, wherein the expandable member is configured todisplace a bone structure when moving between a collapsed configurationand an expanded configuration.
 61. The apparatus of claim 59, whereinthe expandable member is constructed from a polymer having a lowcompliance.
 62. The apparatus of claim 59, wherein the actuator isconfigured to rotate the second shaft relative to the first shaftthrough at least four revolutions in the first direction.
 63. Theapparatus of claim 59, wherein the actuator is configured to rotate thesecond shaft relative to the first shaft through a plurality of discreteincrements.
 64. The apparatus of claim 59, wherein the actuator isconfigured to limit a number of revolutions through which the secondshaft can be rotated relative to the first shaft.
 65. The apparatus ofclaim 59, wherein the actuator is configured to produce an indicationassociated with an angular displacement of the second shaft relative tothe first shaft.
 66. The apparatus of claim 59, wherein: the actuatorincludes: a ratchet wheel configured to be coupled to the first shaft ofthe catheter assembly, the ratchet wheel having a plurality of ratchetteeth; and a knob configured to engage the second shaft of the catheterassembly such that when the knob is rotated relative to the ratchetwheel, the second shaft is rotated relative to the first shaft, the knobincluding at least one pawl configured to complimentarily couple to theplurality of ratchet teeth to prevent the rotation of the knob relativeto the ratchet wheel in the second direction.
 67. The apparatus of claim59, wherein the actuator is coupled to the catheter assembly such thatthe actuator can move longitudinally relative to the first shaftthroughout a predetermined range of motion.